Hidrobiológica (E-Journal)
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Aproximación al conocimiento de los rasgos funcionales de las algas perifíticas y su relación con la calidad del agua en el complejo cenagoso de Zapatosa, Colombia
Get PDFAntecedentes: Las microalgas perifíticas se han utilizado ampliamente como bioindicadores del estrés ambiental. Objetivo: En este trabajo se contrastó la hipótesis de que las características morfofuncionales del ficoperifiton están relacionada con las condiciones físicas, químicas y bacteriológicas del agua en diferentes sistemas acuáticos del Complejo Cenagoso de Zapatosa (CCZ). Métodos: Para ello, se evaluaron algunos aspectos de la morfología funcional de estas algas (dimensión lineal máxima, área superficial, relación superficie-volumen, biovolumen) y de rasgos de formas de vida (formación de colonias, organización en filamentos, presencia de exoesqueleto de sílice, ocurrencia de aerotopos, producción de mucílago y tenencia de flagelos) y se estudió su relación con distintas variables ambientales (oxígeno disuelto, temperatura, pH, conductividad, nutrientes, iones, demandas de oxígeno, carbono orgánico, sólidos disueltos y suspendidos, coliformes fecales y totales). Resultados: Los rasgos funcionales no mostraron diferencias espaciales dentro del CCZ, ni se relacionaron de manera concluyente con las variaciones en las variables fisicoquímicas, excepto por un grado moderado de asociación positiva del biovolumen y el área superficial con las coliformes totales, y negativa del mucílago y la formación de colonias con la dureza total. Conclusiones: Las condiciones de contaminación y deterioro de los distintos sitios del CCZ fueron homogéneas y no permitieron detectar respuestas claras de los rasgos funcionales ante los cambios en la calidad del agua. No obstante, la caracterización de la morfología funcional y de los rasgos biológicos del ficoperifiton del CCZ constituye una primera aproximación a la ecología funcional de este grupo, que permitirá valorar las modificaciones que se produzcan en el futuro ante las intervenciones humanas y los cambios climáticos y ambientales.Background: Periphytic microalgae are commonly used as indicators of environmental stress. Objectives: This study aimed to investigate the relationship between the characteristics of phycoperiphyton and water’s physical, chemical, and bacteriological conditions in various aquatic systems of the Zapatosa Swamp Complex (ZSC). Methods: The research evaluated the functional morphology of these algae (such as maximum linear dimension, surface area, surface-volume ratio, and biovolume) as well as life form traits (including colony formation, filament organization, presence of silica exoskeleton, occurrence of aerotopes, mucilage production, and possession of flagella) and their correlation with different environmental variables (e.g., dissolved oxygen, temperature, pH, conductivity, nutrients, ions, oxygen demands, organic carbon, dissolved and suspended solids, fecal and total coliforms). Results: The study found that the functional traits did not exhibit significant spatial differences within the ZSC, and they were not conclusively related to variations in physicochemical variables, except for a moderate positive association of biovolume and surface area with total coliforms, and a negative association of mucilage and colony formation with total hardness. Conclusions: The pollution and deterioration conditions of the different sites in the ZSC were similar, which did not allow for the clear detection of responses of the functional traits to changes in water quality. Nevertheless, the characterization of the functional morphology and biological traits of the ZSC phycoperiphyton provides an initial understanding of the functional ecology of this group, offering insights that can help assess potential future modifications due to human interventions, as well as climatic and environmental changes
Moluscos dulceacuícolas no nativos de México: estado actual y nuevos registros
Get PDFFreshwater mollusks top the lists of both threatened and endangered species, as well as non-native species potentially harmful to local fauna. The introduction, establishment, and proliferation of non-native freshwater mollusk species have caused significant impacts on the structure and function of aquatic ecosystems, altering feeding patterns, resource competition, and triggering cascading effects throughout local trophic chains. Mexico is particularly vulnerable to these species due to its navigational infrastructure, which facilitates their introduction. The rising popularity of exotic species as pets and the intentional introduction of economically attractive species for artisanal exploitation in certain water bodies further increases the risk. This study presents an updated list of non-native/exotic freshwater gastropod and bivalve species based on a review of geographic records in the literature, data from the National Mollusk Collection, and citizen science platforms. Recent literature revealed new records of exotic species. A total of 13 non-native mollusk species were identified. A total of 496 records were compiled, with the state of San Luis Potosí showing the highest occurrence and Veracruz the greatest diversity of exotic species. All Mexican states, except Campeche and Tlaaxcala, have at least one record of non-native species. Most of these species have ecological, economic, or clinical impacts, with some classified among the 100 worst invasive exotic species. The aquarium trade has been identified as the main probable vector of introduction. It is also likely that unrecorded invasions exist within the country.Los moluscos dulceacuícolas encabezan, por un lado, las listas de especies amenazadas y en peligro de extinción y, por otro, las listas de especies no nativas potencialmente adversas para la fauna local. Así, la introducción, establecimiento y proliferación de especies no nativas de moluscos dulceacuícolas ha generado impactos significativos en la estructura y función de los ecosistemas acuáticos, alterando patrones de alimentación, de competencia por recursos y desencadenando efectos cascada en la cadena trófica local. México es un país vulnerable a estas especies ya que cuenta con una infraestructura de navegación que facilita su introducción. El auge de especies exóticas como mascotas y la introducción de especies económicamente atractivas para la explotación artesanal en ciertos cuerpos de agua incrementa el riesgo. Este trabajo presenta una lista actualizada de especies de gasterópodos y bivalvos dulceacuícolas no nativos / exóticos a través de revisión de registros geográficos en la literatura, registros en la Colección Nacional de Moluscos y aplicaciones de ciencia ciudadana. Se recopiló la literatura reciente con nuevos registros de especies exóticas. Se encontraron 13 especies exóticas de moluscos. Se procesaron 496 registros, siendo San Luis Potosí el estado con mayor ocurrencia y Veracruz el de mayor diversidad de especies exóticas. Todos los estados de México, con la excepción de Campeche y Tlaxcala, tienen por lo menos un registro de especies exóticas. La mayoría tiene impactos ecológicos, económicos o clínicos, algunas se encuentran catalogadas dentro las 100 especies exóticas-invasoras más indeseables. El acuarismo se ha identificado como el probable vector de introducción principal. Pueden existir nuevas invasiones no registradas en el país
Efecto de la suplementación de dos tipos de biomasa microbiana adicionadas a bajos niveles sobre el crecimiento, asimilación y protección hepática en tilapia del Nilo (Oreochromis niloticus)
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Bacteria, cyanobacteria, and other single cell proteins have been considered as reliable ingredients when used to manufacture diets for aquatic organisms. Several nutritional advantages indicate a positive nutritional performance of the microbial biomass. The present study aimed to evaluate the dietary effect of a bacterial biomass and a cyanobacteria (Arthrospira platensis) on growth, nutrient assimilation and hepatic protection in juvenile Nile tilapia (Oreochromis niloticus). Five experimental diets (isoproteic and isoenergetic) were formulated with additive levels of (3 and 6%) of each microbial ingredient. 320 fish were distributed in quadruplicate tanks and fed for 28 days. At the end of the feeding assay, there were no significant differences in weight gain and feed conversion ratios among treatments. In order to estimate the proportion assimilation of nutrients supplied by the experimental ingredients, the isotopic values of nitrogen were analyzed in ingredients and fish muscle tissue. The isotopic values of diets were transferred to muscle tissue fast, and an isotopic equilibrium was achieved. Results indicated that diets containing 3% of microbial biomass supplied structural nitrogen to muscle biosynthesis. With the objective of estimating the degree of hepatic protection promoted by the ingredients, a diesel exposition was conducted. Results indicated that there was a significant increase in the enzymatic activity of carboxylesterase in all dietary treatments. Glutathione S-tranferase activity increased in fish that were previously fed Arthrospira biomass. Overall results indicate positive physiological responses elicited by the dietary addition of micriobial biomass.Objetivos. Se diseñó un experimento nutricional en el cual se evaluó el efecto de la sustitución parcial de harina de pescado (HP) por biomasa bacteriana y espirulina (Arthrospira platensis) sobre el crecimiento, asimilación de nutrientes y protección hepática en tilapia del Nilo. Métodos. Para ello se formularon cinco tratamientos (dietas isoprotéicas e isoenergéticas): La dieta control consistió en 100% de la proteína aportada por HP, los tratamientos 97HP:3AP y 94HP:6AP consistieron en 3 y 6%, respectivamente, de proteína aportada por Arthrospira y 97HP:3BB y 94HP:6BB en 3 y 6%, respectivamente, de la proteína aportada por biomasa Bacteriana. Se utilizaron 320 alevines (0.8(0.05 g peso inicial), distribuidos en 16 organismos por acuario (4 acuarios por tratamiento). Durante 28 días se ofreció alimento ad libitum en tres porciones por día, iniciando con 10% de la biomasa del acuario. Resultados y conclusiones. Los parámetros de rendimiento entre tratamientos fueron similares. Los valores isotópicos del nitrógeno determinados en los ingredientes experimentales y en tejido muscular de los peces permitió estimar la asimilación proporcional relativa del nitrógeno dietario aportado por los ingredientes experimentales. Se observó que, incluso a los niveles evaluados, ambas fuentes microbianas aportaron nitrógeno estructural durante la biosíntesis de músculo. Al evaluar el grado de protección hepática conferido por los ingredientes en peces expuestos a diésel, todos los tratamientos presentaron un incremento en la actividad de la enzima carboxilesterasa. En cambio, la actividad de glutatión-S-transferasa, se incrementó solamente en los peces que consumieron las dietas con 3 y 6% de espirulina. La adición de las fuentes microbianas en la mayoría de los casos promovió respuestas fisiológicas positivas al observarse que los niveles de expresión enzimática no presentaron alteraciones significativas
Morpho-biometric relationships and allometry of the “black clam” (Anadara mazatlanica) from two coastal lagoons in the southeastern Gulf of California
Get PDFBackground. Phenotypic plasticity in bivalve mollusks, such as Anadara mazatlanica (“black clam”), is influenced by both external environmental and internal biological factors, which causes changes in the metric variables of the shell and in the relationship between them. Goals. This study examined the association of environmental variables with the biometric indices and morphometric relationships of A. mazatlanica collected from two sites in the southeastern Gulf of California from March 2022 to February 2023. Methods. Monthly, environmental variables of the water were obtained (temperature, dissolved oxygen, salinity, pH, organic matter, inorganic matter, total suspended solids and chlorophyll a); also every month, samples of 120 clams were taken from the El Colorado (ECL) and Navachiste Lagoon (NL) systems in Sinaloa, Mexico, to obtain the height, length, and width of the shell (mm). Results. The clams from ECL were significantly larger in length, but exhibited lower shell compactness and cupping compared to those from NL (p < 0.05). At both locations, morphometric equations for A. mazatlanica displayed a linear positive relationship, with negative allometry (b < 1). The most representative growth ratios were shell width/shell height for ECL (R² = 0.80) and shell width/shell length for NL (R² = 0.78). Temperature and salinity were negatively related to shell dimensions in both locations. Conclusions. Significant monthly and annual variations were observed in all morphometric variables between the two populations, indicating that A. mazatlanica experiences environmental stress but also exhibits resilience to local conditions. This is the first morpho-biometric analysis of the “black clam” in this region, providing valuable insights for the species' management.Background. Phenotypic plasticity in bivalve mollusks, such as Anadara mazatlanica (“black clam”), is influenced by both external environmental and internal biological factors, which causes changes in the metric variables of the shell and in the relationship between them. Goals. This study examined the association of environmental variables with the biometric indices and morphometric relationships of A. mazatlanica collected from two sites in the southeastern Gulf of California from March 2022 to February 2023. Methods. Monthly, environmental variables of the water were obtained (temperature, dissolved oxygen, salinity, pH, organic matter, inorganic matter, total suspended solids and chlorophyll a); also every month, samples of 120 clams were taken from the El Colorado (ECL) and Navachiste Lagoon (NL) systems in Sinaloa, Mexico, to obtain the height, length, and width of the shell (mm). Results. The clams from ECL were significantly larger in length, but exhibited lower shell compactness and cupping compared to those from NL (p < 0.05). At both locations, morphometric equations for A. mazatlanica displayed a linear positive relationship, with negative allometry (b < 1). The most representative growth ratios were shell width/shell height for ECL (R² = 0.80) and shell width/shell length for NL (R² = 0.78). Temperature and salinity were negatively related to shell dimensions in both locations. Conclusions. Significant monthly and annual variations were observed in all morphometric variables between the two populations, indicating that A. mazatlanica experiences environmental stress but also exhibits resilience to local conditions. This is the first morpho-biometric analysis of the “black clam” in this region, providing valuable insights for the species' management
Expansión de Pez gato Rafael moteado, Agamyxis pectinifrons (Cope 1870) (Siluriformes: Doradidae), en el sureste de México
Get PDFBackground. Spotted Raphael catfish, Agamyxis pectinifrons, is native to the Amazon River basin. Its presence in southeastern Mexico was reported for the first time in 2021. Objective. Document the expansion of the spotted catfish in the Grijalva-Usumacinta basin. Methods. Surveys were carried out on finfish and river shrimp fishermen to detect the presence of A. pectinifrons. This was done with the use of photographs in nearby fishing communities, where the first reports were made. Results. The presence of A. pectinifrons was detected in the towns of Tabasquillo and Chichicastle 1st Section, Tabasco, in October and November 2023, respectively. The first reports of this species had been recorded in September 2020 in Villahermosa, Tabasco and in December 2021 in the Pichucalco area, Chiapas. Therefore, in this work an increase in its extension of approximately 50 km in three years is recorded. This progress could be considered slow, if we compare it with that of Pterygoplichthys spp, which in a few years made significant progress throughout the Grijalva-Usumacinta basin. To analyze this situation, it will be necessary to carry out studies on the possible causes. Conclusion. The speed of extension is slow, and the presence of A. pectinifrons extends over 50 km in the Grijalva-Usumacinta basinAntecedentes. El pez gato Rafael punteado, Agamyxis pectinifrons, es nativo de la cuenca del Río Amazonas. Su presencia en el sureste de México fue reportada por primera vez en el 2021. Objetivo. Documentar la expansión del pez gato punteado en la cuenca del Grijalva-Usumacinta. Métodos. Se realizaron encuestas a pescadores de escama y de camarón de río, para detectar la presencia de A. pectinifrons, esto se realizó con la utilización de fotografías en las comunidades pesqueras cercanas, donde se realizaron los primeros reportes. Resultados. Se detectó la presencia de A. pectinifrons en las localidades de Tabasquillo y Chichicastle 1era Sección, Tabasco, en octubre y noviembre del 2023, respectivamente. Los primeros reportes de esta especie fueron registrados en septiembre del 2020 en Villahermosa, Tabasco y en diciembre del 2021 en la zona de Pichucalco, Chiapas. Por lo que en este trabajo se registra un aumento en su extensión de aproximadamente 50 km en tres años. Este avance se podría considerar lento, si lo comparamos con el de Pterygoplichthys spp que en pocos años tuvo un avance significativo en toda la cuenca del Grijalva-Usumacinta. Para analizar esta situación será necesario realizar estudios sobre las posibles causas. Conclusión. La velocidad de extensión es lenta, y se extiende la presencia de A. pectinifrons en 50 km en la cuenca Grijalva-Usumacinta
Diferenciación morfométrica del Género Corbicula (Megerle von Mühlfeld, 1811) en las cuencas Grijalva, Usumacinta y Papaloapan
Get PDFSoutheastern Mexico has an important network of river and wetland ecosystems, where invasive species are recorded that represent a threat to biodiversity and produce alterations in natural ecosystems. In this study, the species of the Corbicula genus were identified based on the morphometric differentiation of the organisms collected in the Grijalva, Usumacinta and Papaloapan basins. The organisms belong to the Reference Collection on Aquatic Organisms of the Southeast: Macroinvertebrates and Fish of ECOSUR, collected in diurnal samplings with a multi-habitat effort in 25 locations between the years 2013 to 2018, the physicochemical parameters of the water were also recorded. Regarding water parameters, the maximum values of pH (8.5), temperature (29°C), and oxygen saturation (76.6%) were recorded in the Usumacinta basin, while conductivity (546 mScm-1) and salinity (0.27‰) were recorded in Papaloapan. 200 organisms corresponding to each basin were selected, these were measured (length, width and height) and weighed individually. Of the total organisms analyzed, 59% of the abundance was for Corbicula fluminea (Cfl), while Corbicula largillierti (Cla) represented 41%. The Grijalva and Usumacinta basins recorded the highest abundance of Cfl with 84% and 75%, on the contrary, in Papaloapan Cla is the predominant species representing 80% of the records in this basin. The highest mean values for measurements and weight were for Cla. In the case of Cfl, the maximum mean value for weight was recorded in the Grijalva basin, while the length, height and width were in the Usumacinta basin. For both species, the mean values for all measurements and weight were recorded in the Papaloapan basin. This work contributes with a new invasive species in the Grijalva, Usumacinta and Papaloapan basins.El sureste de México posee una importante red de ecosistemas fluviales y humedales, que presentan especies no nativas que amenazan a la biodiversidad y producen alteraciones en los ecosistemas naturales. El género Corbicula tiene una amplia distribución en México, con taxonomía compleja, y recientemente se ha documentado la coexistencia de dos morfologías diferentes. En este trabajo se analizaron las diferencias morfométricas de estas poblaciones. Se eligieron 600 organismos depositados en la Colección de referencia de organismos acuáticos de ECOSUR (CROASUR), recolectados en 25 localidades de las cuencas Grijalva (CG), Usumacinta (CU) y Papaloapan (CP) entre los años 2013 al 2018. 200 organismos por cuenca fueron medidos (longitud, ancho y altura) y pesados individualmente. Se registraron los parámetros fisicoquímicos del agua. Los valores máximos de pH (8.5), temperatura (29 °C), y saturación de oxígeno (76.6%) se presentaron en la cuenca Usumacinta, mientras que los de conductividad (546 mScm-1) y la salinidad (0.27 ups) lo fueron en el Papaloapan. Se confirma la coexistencia de dos especies del género Corbicula en las cuencas del sureste mexicano, debido a las diferencias significativas en la talla y peso, así como en los rasgos morfológicos distintivos. Del total de organismos, 59 % de la abundancia fue para Corbicula fluminea (Cfl), mientras que Corbicula largillierti (Cla) representó 41 %. Las cuencas Grijalva y Usumacinta registraron la mayor abundancia de Cfl con 84 % y 75 % respectivamente; por el contrario, en Papaloapan Cla fue la especie dominante con 80 % de los registros en esta cuenca. Los máximos valores promedio de las medidas y el peso fueron para Cla. En el caso de Cfl se registró el valor promedio máximo de peso en la cuenca Grijalva, mientras que la longitud, altura y ancho fueron en la cuenca Usumacinta
“Diversity and community structure of microbial assemblages from evaporitic ponds of Northwestern México”
Get PDFBackground. Evaporitic environments are extreme habitats due to the combined effects of several environmental factors such as temperature and salinity, despite, their host a great diversity of prokaryotes, most poorly studied but with a great biotechnological potential. The Vizcaíno region in Northwestern Mexico represents an ideal area for the exploration of saline environments that result from their geological and contemporary history, particularly, the salty ponds known as “Las Charcas” represent an ideal model due to the null anthropogenic activity. Goal. To explore the factors that determine the structure community of bacteria and archaea residing in sediments with different levels of salinity. Methods. Six different ponds were sampled during January of 2018, after it, a fragment of 16S rRNA was amplified and sequenced using NGS. Alpha and beta diversity indices were estimated, on the other hand, Webb’s NTI and NRI metrics were used to evaluate which factors determine the phylogenetic community structures in each pond, finally, to evaluate which taxa are driven by selective pressures, a neutral test model was performed. Results. Diversity levels showed a positive correlation with salinity and organic matter, however, none of the biogeochemical parameters evaluated explained significantly the differences in composition among sampled ponds. Conclusions. The microbial structure community in the sediments of the ponds analysed is shaped by both deterministic and stochastic processes, including homogeneous selection, dispersal and ecological drift.Antecedentes. Los ambientes evaporiticos representan hábitats extremos por el efecto combinado de una serie de factores tales como temperatura y salinidad, a pesar de ello, alojan una gran diversidad de organismos procariontes, la mayoría poco estudiados pero con un gran potencial biotecnológico. La región del Vizcaíno en el Noroeste de México representa un área ideal para la exploración de ambientes salinos, los cuales son el resultado de su historia geológica y contemporánea, en particular, las pozas conocidas como “Las Charcas” representan un excelente modelo de estudio por su nula perturbación antrópica. Objetivo. Explorar los factores que determinan la estructura comunitaria de las bacterias y arqueas que residen en los sedimentos de pozas de evaporación con diferentes niveles de salinidad. Método. Seis pozas de evaporación fueron muestreadas durante enero de 2018, posteriormente, se amplificó y secuenció un fragmento de la fracción 16S rRNA mediante SNG. Se calcularon estimadores de diversidad alfa y beta, por otro lado, las métricas NTI y NRI descritas por Webb se utilizaron para discriminar los factores que determinan la estructura filogenética de las comunidades en cada poza, finalmente, para estimar que taxa podrian estar sujetos a presiones selectivas se realizó un modelo neutral. Resultados. Los niveles de diversidad mostraron una correlación positiva con la salinidad y la materia orgánica, sin embargo, ninguno de los parámetros biogeoquímicos evaluados permitió explicar las diferencias significativas encontradas al comparar las pozas. Conclusiones. La estructura de las comunidades que residen en los sedimentos de las pozas analizadas está determinada por factores tanto determinísticos como estocáticos, incluyendo selección homogenizadora, dispersión y deriva ecológica
Anticoagulant activity of sulfated polysaccharides obtained from the brown seaweed Stephanocystis dioica
Get PDFBackground: Brown algae are recognized as a source of sulfated polysaccharides of great economic value and importance in biomedical studies due to their diverse biological activities such as anticoagulant, antioxidant, antiviral, among others. Goals: In this study, an aqueous extract from the brown seaweed Stephanocystis dioica was evaluated to determine its potential anticoagulant activity. Methods: An aqueous extraction was carried out at room temperature to obtain sulfated polysaccharides, which were semi-purified by fractional precipitation with ethanol to obtain three fractions. These fractions were employed in prothrombin time (PT) and activated partial thromboplastin time (aPTT) assays to evaluate anticoagulant activity at different concentrations (6.25-100 µg mL-1). The partial chemical composition (fucose, uronic acids, and sulfates) and SO4/sugar residue ratio were also determined. Results: In the PT assay, at a concentration of 100 µg mL-1, fraction F3 exhibited the greatest coagulation time (76 s), which was four times that of the control. In the aPTT assay, the three fractions extended the control time (28.8 s) to more than 300 s at a concentration of 100 µg mL-1. Partial chemical analysis showed that fractions F1, F2, and F3 are sulfated heteropolysaccharides rich in fucose, with lower concentrations of uronic acids and other sugars. In the infrared spectrum, the observed vibrations at 820 cm-1 indicate a twist of the sulfate group at the equatorial position of the sugar ring at 2-O and/or 3-O positions. Conclusions: The results showed that sulfated polysaccharide from Stephanocystis dioica has potential anticoagulant activity.Antecedentes: Las algas pardas son reconocidas como fuente de polisacáridos sulfatados de gran valor económico e importancia en estudios biomédicos debido a sus diversas actividades biológicas como anticoagulante, antioxidante, antiviral, entre otras. Objetivos: Para este estudio se evaluó un extracto acuoso obtenido del alga parda Stephanocystis dioica para determinar su potencial actividad anticoagulante. Métodos: Se realizó una extracción acuosa a temperatura ambiente para obtener polisacáridos sulfatados, los cuales se semipurificaron por precipitación fraccionada con etanol, obteniendo tres fracciones. Estas fracciones se emplearon en ensayos de tiempo de protrombina (TP) y tiempo de tromboplastina parcial activada (TTPa) para evaluar la actividad anticoagulante a diferentes concentraciones (6.25-100 μg mL-1). También se determinó la composición química parcial (fucosa, ácidos urónicos y sulfatos) y la relación SO4/residuos de azúcar. Resultados: En el ensayo TP, a una concentración de 100 μg mL-1, la fracción F3 mostró el mayor tiempo de coagulación (76 s), el cual fue cuatro veces superior al tiempo del control. En el ensayo TTPa, las tres fracciones prolongaron el tiempo del control (28.98 s) a más de 300 s a una concentración de 100 μg mL-1. El análisis químico parcial mostró que las fracciones F1, F2 y F3 son heteropolisacáridos sulfatados ricos en fucosa, con menores concentraciones de ácidos urónicos y otros azúcares. En el espectro infrarrojo, las vibraciones observadas a 820 cm-1 indican una torsión del grupo sulfato en la posición ecuatorial del anillo de azúcar en las posiciones 2-O y/o 3-O. Conclusiones: Los resultados mostraron que el polisacárido sulfatado de Stephanocystis dioica tiene una potencial actividad anticoagulante
ALTERAÇÕES CLIMÁTICAS E ÁGUAS SUPERFICIAIS NO NOROESTE DO ESTADO DO MÉXICO
No full textOne of the main problems represented by climate change is the uncertainty of its impact on social structures, biotic and abiotic elements, biogeochemical and emerging processes, among others; one of the most important is the water cycle, this connection is fundamental to manage the future water supply in a integrated way in one of the most vulnerable areas in the center of the Mexican Republic, as is the case of the northwest of the State of Mexico; to identify it, a climate projection has been made to the year 2050, considering the representative concentration pathway 8. 5 (RCP) adjusted by the bias correction methodology, which shows us a possible variation in the average precipitation, since the estimated average for the dry season (115.98 mm) and rainy season (774.61) in the period 1991-2020; it would go to 48. 43 mm (dry season) and 282.70 mm (rainy season) for the period 2021-2050, as well as a temperature increase of 3.6°C for the same year, being the main contribution of this research, the behavior of surface water within the study area under these possible scenarios. However, we should mention, these results respond to a future assumption in which inaction prevails and the objectives of international instruments such as the Paris agreement and national ones such as the nationally determined contributions are not achieved.Antecedentes: los posibles impactos del cambio climático sobre el agua superficial en el noroeste del Estado de México podrían afectar su cantidad y distribución en un futuro próximo. Objetivo: cuantificar los recursos hídricos superficiales de la zona de estudio y determinar su comportamiento hacia el año 2050, considerando la influencia del cambio climático, brindaría herramientas que podrían ser utilizadas para su adecuada gestión. Método: se elaboró un balance hídrico superficial (BHS) para la época de sequía (de marzo a mayo) y la época de lluvias (de junio a septiembre) utilizando fórmulas empíricas para cada uno de los procesos. Posteriormente, se determinó un escenario de cambio climático contemplando la vía representativa de concentración 8.5 (RCP, por sus siglas en inglés). Se realizó un tratamiento y ajuste de la información climatológica empleando la metodología de corrección de sesgos. Resultados: los valores iniciales del BHS para el periodo de 1991 a 2020 muestran una precipitación media de 115,98 mm en temporada de sequía y de 774,61 mm en temporada de lluvias. Al incorporar el escenario de cambio climático tratado con la reducción de sesgos, se proyectó el BHS al año 2050, observándose una precipitación media de 48,43 mm en época de secas y de 282,70 en época de lluvias, así como un incremento en la temperatura media de 3,6 °C. Conclusiones: El posible impacto del cambio climático sobre el agua superficial del noroeste del Estado de México afectaría a las actividades humanas relacionadas con el agua, alterando la dinámica social de la población.Um dos principais problemas representados pelas alterações climáticas é a incerteza do seu impacto nas estruturas sociais, elementos bióticos e abióticos, processos biogeoquímicos e emergentes, entre outros; entre os mais importantes, identificamos o ciclo da água, esta relação é essencial para gerir o futuro abastecimento de água de uma forma abrangente numa das áreas mais vulneráveis do centro da República Mexicana, como é o caso do noroeste do Estado do México; para o identificar, foi feita uma projeção climática para o ano 2050, considerando a via de concentração representativa 8. 5 (RCP) ajustada pela metodologia de correção de viés, o que nos mostra uma possível variação na precipitação média, uma vez que a média estimada para a estação seca (115,98 mm) e a estação chuvosa (774,61) no período 1991-2020 passaria para 48. 43 mm (estação seca) e 282,70 mm (estação chuvosa) para o período 2021-2050, bem como um aumento de temperatura de 3,6°C para o mesmo ano, sendo a principal contribuição desta investigação o comportamento das águas superficiais na área de estudo sob estes possíveis cenários. No entanto, devemos mencionar que estes resultados respondem a um cenário futuro em que a inação prevalece e os objectivos dos instrumentos internacionais, como o Acordo de Paris, e nacionais, como as contribuições determinadas a nível nacional, não são alcançados
Ctenophores and siphonophores are alternative hosts in the life cycle of didymozoids in the Gulf of California: Didymozoid in gelatinous zooplankton
No full textBackground. Few studies exist of parasites of zooplanktonic organisms. This situation increases the odds to discover new species of parasites, new types of parasitic interactions, and reports that increase the geographic distribution ranges worldwide. Goals. We report a new parasitic interaction between the metacercariae of didymozoids (Digenea) with a ctenophore and a siphonophore species (gelatinous zooplankton) based on observations of live zooplankton in the Gulf of California. Methods. Zooplankton was collected during day and night using a standard Bongo net in an oceanographic cruise carried out during June-July 2016 in the Gulf of California. Results. We observed four ctenophore specimens of Pleurobrachia bachei (intensity of parasitism = 2-3 parasites per host) and a siphonophore specimen of Muggiaea atlantica (intensity = 1) parasitized with a total of nine metacercariae Didymozoidae morphologically identified as larval type Monilicaecum. Molecular analysis of didymozoid metacercariae was not attempted here, but a molecular identification of morphologically similar didymozoids was previously reported infecting chaetognaths of the Gulf of California. Didymozoids were found in three different microhabitats in the P. bachei and in the subumbrellar cavity of M. atlantica. Conclusions. We do the first record of didymozoid parasitizing ctenophores and siphonophores that also represent new geographic records for these parasites in the Gulf of California extending its distribution range from the Atlantic Ocean to the Pacific Ocean.Background. Few studies exist of parasites of zooplanktonic organisms. This situation increases the odds to discover new species of parasites, new types of parasitic interactions, and reports that increase the geographic distribution ranges worldwide. Ctenophores and siphonophores are relevant intermediary or paratenic host of numerous marine endoparasites due their carnivorous habits. Goals. We report the parasitic interaction between the metacercariae of didymozoids (Digenea) with a ctenophore and a siphonophore species based on observations of alive gelatinous zooplankton in the Gulf of California. Methods. Zooplankton was collected from 27 oceanographic stations during day and night using a standard Bongo net in an oceanographic cruise carried out during June-July 2016 in the Gulf of California. Zooplankton was observed alive immediately after collection. Results. We observed four ctenophore specimens of Pleurobrachia bachei (intensity of parasitism = 2-3 parasites per host) and a siphonophore specimen of Muggiaea atlantica (intensity = 1) parasitized with a total of nine metacercariae Didymozoidae morphologically identified as larval type Monilicaecum. Didymozoids were found in two different sampling stations, and in three different microhabitats (pharynx, meridional canal below of the ctene rows, and pharyngeal canal) in the P. bachei and in the subumbrellar cavity of M. atlantica. Conclusions. We proposed that ctenophores and siphonophores act as alternative host in the life cycle of didymozoids. Didymozoids infecting ctenophores and siphonophores are only know from the Atlantic Ocean. We do the first record of didymozoid parasitizing ctenophores and siphonophores in the Gulf of California, extending its distribution range from the Atlantic Ocean to the Pacific Ocean