Hidrobiológica (E-Journal)
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Seasonal vertical distribution of fish larvae in the southern Gulf of Mexico
Get PDFChanges in the composition and abundance of fish larvae in the water column were analyzed throughout an annual cycle (1994-1995) in the southern Gulf of Mexico, in order to establish the difference between the habitat of the larvae and the effect of oceanographic events on larval vertical distribution. The study area comprised the continental shelf off Tabasco and Campeche in the southern Gulf of Mexico. Samples were collected at five water column levels: 0-6, 6-12, 12-18, 45-55 and 95-105 m. A total of 118 taxa were identified, 52 were dominant species, 33 were larvae of neritic parents and 19 were larvae of mesopelagic parents. The results indicate that the water column presented two layers above the 105 m depth: a surface layer (0-18 m) and a deep layer (45-105 m). The greatest density of larval species that inhabit neritic areas as adults was recorded in the surface layer (0-18 m), while larvae of which the parents inhabit mesopelagic areas were found in the deep layer (45-105 m). The mixing of the water column was the most important physical factor regarding the variation in the vertical distribution of the larvae of both groups, particularly in winter. However, the biology of each species and the habit to occupy a particular depth was the most important factor that determined their distribution in the water column
Lethal effects of five metals on the freshwater rotifers Asplanchna brigthwellii and Brachionus calyciflorus
Get PDFAcute toxicity tests of five metals (aluminum, cadmium, iron, lead,zinc) were performed to determine LC50 values in two species of freshwater rotifers: Asplanchna brigthwellii and its prey Brachionus calyciflorus. We conducted the tests using neonates less than 24 hr-old, each test consisted of five replicates, negative control and five metal concentrations (Al, Cd, Fe, Pb, Zn). We found that the prey rotifer B. calyciflorus was more sensitive to Al, Cd, Pb and Fe than the predator rotifer A. brightwellii. For both rotifers Cd was the most toxic of the five metals. It was established that the strain of B. calyciflorus studied is sensitivewhen comparedwith otherB. calyciflorus strains and other species and genera ofthe family Brachionidae. In the other hand, LC50 values of A. brigthwellii are compared with rotifer and copepod predators
La sensibilidad del grupo coliforme como indicador de la presencia de enterobacterias patógenas en cuatro cuerpos acuáticos de México
Get PDFMicrobiological pollution in water bodies is characterized through the detection of indicator organisms like total coliform (TC) and fecal coliform (FC) bacteria. The objective of the present paper was to determine the sensibility of these indicators of the presence of pathogenic enterobacteria in four Mexican aquatic systems. Two with major anthropogenic influence: Patzcuaro Lake and Xochimilco Lake ecosystem; and two with less: Metztitlan Lagoon and Zirahuen Lake. TC and FC were quantified with the Most Probable Number technique in water and sediment and enteric bacteria were isolated in water using selective culture media. The sensibility index, the risk attributable, and the presenceabsence of indicators and pathogens were evaluated. Patzcuaro and Xochimilco showed high bacterial pollution. The sediment presented higher concentrations of total and fecal coliforms than water. FC were the most reliable indicators to predict the presence of Salmonella and Shigella, with a sensitivity of 60 and 75%, an attributable risk of 58 and 67% for each genus. FC showed a presence-absence relationship with a percentage of true cases of 82 to 88%. In contrast, TC showed a low attributable risk, inferior to 27% and a high percentage of false positives (65%), which impede to consider it a good indicator. It is convenient to evaluate the presence of indicators and pathogens simultaneously to determine the sanitary risk when characterizing microbial water quality in aquatic ecosystems.La contaminación microbiológica en los cuerpos acuáticos se caracteriza a través de la detección de organismos indicadores como las bacterias coliformes totales (CT) y fecales (CF). El objetivo de este trabajo fue determinar la sensibilidad de estos indicadores para predecir la presencia de enterobacterias patógenas en cuatro cuerpos acuáticos mexicanos. Dos con mayor influencia humana: lago de Pátzcuaro, Mich. y ecosistema lacustre de Xochimilco, D. F y dos con menor: la laguna de Metztitlán, Hgo. y el lago Zirahuén, Mich. Se cuantificaron coliformes totales y coliformes fecales en agua y sedimento por la técnica del Número Más Probable y se aislaron bacterias entéricas del agua mediante el uso de medios de cultivo selectivos. Se evaluaron: el índice de sensibilidad, el riesgo atribuible y la presenciaausencia de indicadores y patógenos. Pátzcuaro y Xochimilco mostraron alta contaminación bacteriana. El sedimento presentó mayor concentración de CT y CF que el agua. Los CF mostraron ser indicadores más confiables para predecir la presencia de Salmonella y Shigella, con una sensibilidad para cada género de 60 y 75% y un riesgo atribuible del 58 y 67%. Los CF mostraron una relación presencia-ausencia con un porcentaje de casos verdaderos del 82 a 88%. En contraste, los CT mostraron un riesgo atribuible bajo (inferior a 27%) y un alto porcentaje de falsos positivos (65%), lo que impidió considerarlo como un buen indicador. Es conveniente evaluar la presencia de indicadores y patógenos simultáneamente para determinar el riesgo sanitario al caracterizar la calidad microbiológica en ecosistemas acuáticos
Composición, abundancia del zooplancton y calidad de agua en un microreservorio en el estado de Morelos
Get PDFThe aim of the present work was to analyze the zooplankton composition, abundance and species richness at Huitchila microreservoir (called bordo in Spanish), Morelos, Mexico and their relationship with environmental conditions between September 2010 and September 2011. Sixteen zooplankton species belonging to three main groups were identified at the bordo: 11 rotifers, 3 cladocerans, and 2 copepods. The most frequent species was the copepod Arctodiaptomus dorsalis, occurring in 100% of the samples, with a density of 1 182 org/L. Among the cladocerans, Diaphanosoma birgei was the most frequent and abundant (100% and 85 org/L, respectively). The most abundant rotifer species was Brachionus falcatus (1 511 org/L) and the most frequent was B. caudatus (92%). The family Brachionidae had the highest species richness in the surveyed system. The highest zooplankton abundances and species richness were recorded during the dry season. Huitchila microreservoir is a eutrophic system, with warm water (20.3-28 °C), high availability of dissolved oxygen (4.1-16.2 mg/L), slightly alkaline, hard waters, with low conductivity (693-1258 µS/cm). This aquatic system is productive and has high food availability for the tilapia Oreochromis niloticus, a local fisheries resource.El objetivo de este trabajo fue analizar la composición, abundancia y riqueza de especies del zooplancton en el bordo Huitchila, Morelos, México y su relación con los factores ambientales durante el periodo septiembre de 2010 a septiembre de 2011. Se identificaron 16 especies pertenecientes a tres grupos principales: 11 rotíferos, 3 cladóceros y 2 copépodos. La especie más frecuente fue el copépodo Arctodiaptomus dorsalis, presente en el 100% de las muestras, con densidad de 1 182 org/L. Entre los cladóceros la especie más frecuente y abundante fue Diaphanosoma birgei (100% y 85 org/L, respectivamente). La especie de rotíferos más abundante fue Brachionus falcatus (1 511 org/L) y la más frecuente B. caudatus (92%). La familia Brachionidae registró la mayor riqueza de especies en el sistema estudiado. La máxima riqueza de especies y abundancia de zooplancton se registró en la época de secas. El microreservorio se considera eutrófico, con aguas cálidas (20.3-28 °C), bien oxigenadas (4.1-16.2 mg/L), ligeramente alcalinas, duras y de baja conductividad (693-1258 µS/cm). Este sistema presenta buena productividad y alta disponibilidad de alimento necesario para la nutrición de la tilapia Oreochromis niloticus, especie que es explotada localmente por los pescadores
Composición, abundancia y distribución de Pteropoda (Mollusca: Gastropoda) en la zona nerítica, del sur del Golfo de México (Agosto, 1995)
Get PDFThe composition, distribution, and abundance of pteropods were analyzed in relation to hydrographic conditions of the water column (0 to 105 m) in the Gulf of Mexico. Up to 95 samples of zooplankton were collected during August 1995 at 28 stations arranged in five transects on the continental shelf off the main lagoonal systems in the southern Gulf of Mexico, from the Coatzacoalcos River inlet to Paso Real inlet of Términos lagoon . Samples were collected at five depth ranges. Three of the identified taxa constituted 90% of the total pteropod abundance: Creseis acicula f. acicula (72.7%), C. acicula f clava (8.2%), and Limacina trochiformis (9.3%). The highest density of the group occurred within the first 18 m, but 19 of the 39 groups registered were absent from the surface layer (0-6 m), and others had low densities. The results of a CCA suggest that not one parameter by itself determines the distribution of these organisms in the water column, but the habitat of the species does. Species with tropical/subtropical and coastal affinities were the most abundant and occurred mainly in the surface layer, while the oceanic forms were less abundant and occurred mainly in the deep layers probably resulting from the inflow of oceanic water toward the shelf at its deepest layers.Se analizó la composición distribución y abundancia de los pterópodos en relación a las condiciones hidrográficas de la columna de agua (0 a 105 m) en el Golfo de México. Durante agosto de 1995, se recolectaron 95 muestras de zooplancton en 28 estaciones sobre la plataforma continental, distribuidas en cinco transectos frente a los principales sistemas lagunares del sur del Golfo de México, desde la desembocadura del rio Coatzacoalcos, hasta Boca de Paso Real de la Laguna de Términos. Las muestras se recolectaron en cinco niveles de profundidad. De los taxa identificados, tres de ellos constituyeron el 90% de la abundancia total de pterópodos: Creseis acicula f. acicula (72.7%), C. acicula f. clava (8.2%) y Limacina trochiformis (9.3%). La mayor densidad del grupo ocurrió en los primeros 18 m, sin embargo, 19 de los 39 grupos registrados, no ocurrieron en la capa más superficial (0 a 6 m) y otros lo hicieron con bajas densidades. Los resultados de Análisis Canónico de Correspondencia (ACC) permiten considerar que ningún parámetro por si solo determina la distribución de estos organismos en la columna de agua, pero en cambio sí el hábitat. Las especies de afinidad tropical/subtropical y hábitat nerítico fueron las más abundantes y ocurrieron principalmente en la capa superficial, en tanto que las formas oceánicas fueron las de menor abundancia y ocurrieron principalmente en las capas profundas, probablemente como resultado de la entrada de agua oceánica a la plataforma en su parte más profunda
Persistent organic pollutants in sediment cores of Laguna El Yucateco, Tabasco, Southeastern Gulf of Mexico
Get PDFInformation is presented on the content of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in sediment cores collected in the coastal ecosystem of Laguna El Yucateco, located in the tropical southeastern Gulf of Mexico. The ecosystem lies in a region where the human population is socially and economically limited, and it is subjected to great environmental pressure derived mainly from the oil industry. The vertical profiles data show that concentration of the various persistent organic pollutants (POPs) does not present a homogeneous pattern, making evident that the levels of these pollutants depend strongly on anthropological discharges from industrial, urban and farming sources, as well as on those originated by sanitary control measures for the prevention of tropical diseases such as malaria. Potentially carcinogenic compounds were found, including benzo(a)pyrene, aldrin and polychlorinated biphenyls congeners that have been classified as endocrine disruptors. The magnitude of the concentration of persistent organic pollutants is alarming, as values were above the sediment quality criteria established to prevent damage to benthic organisms. Coastal sediments also represent an environmentally risky secondary source of pollutants
Patrones de distribución de clorofila a y producción primaria en aguas del Golfo de México y del Mar Caribe
No full textAn aceanographic cruise was carried out in the Summer 1994 in the Gulf of Mexico and Caribbean Sea in order to study the spatial variability (horizontal and vertical) of the total chlorophyll a and primary production in relation to thermal structure, irradiance, and the nutricline position in the water column. The highest production rates were measured on the Yucatan shelf (0.84 and 2.11 gC.m-2.d-1) while in the Gulf of Mexico and Caribbeab Sea the rates were much lower (0.07-0.14 gC.m-2.d-1). Vertical profiles with deep chlorophyll maxima (0.16 to 4.24 mg.m-3) were always situated below the mixed layer, between 20 and 120m deep in neritic and oceanic waters, respectively, at low light intensities (between 0.2 and 5% of I) and sometimes in relation to the nutricline. In the Gulf of Mexico and in the Caribbean Sea a vertical profile types which is characteristics for tropical oligotrophic waters, with low chlorophyll concentrations, a deep maximum near the nutricline and low primary production was found. In the Yucatan shelf the profile approximates to the productive extreme of typical tropical structure, with higher chlorophyll concentration, primary production and a shallow thermocline. In oligotrophic waters the phytoplankton fraction < 10um contributes with 50 to 100% of the total chlorophyllic biomass while, in eutrophic waters its contribution ranges between 20 and 67%.En el verano de 1994 se llevó a cabo una ccampaña oceanográfica en el Golfo de México y en el Mar Caribe noroccidental con el objetivo de estudiar algunas caracteríaticas espaciales (horizontales y verticales) de la distribución de la clorofila a y de la producción fitoplanctónica relacionadas con la estructura térmica, luminosa y con la ubicación de la nutriclina en la columna de agua. Se evidenciaron diferencias geográficas en la región estudiada: las aguas de la plataforma de Yucatán fueron las más productivas, con valores de 0.84 y 2.11 gC, m2. d-1 mientras que las estaciones del Golfo de México y del Mar Caribe presentaron valores muy bajos (entre 0.07 y 0.14 gC.m2.d-1). Se obtuvieron perfiles verticales donde se observan máximos de clorofila a (de 0.16 a 4.24 mg.m-3) ubicados siempre por debajo de la capa de mezcla, a profundidades entre 20 y 120m en estaciones neríticas y oceánicas, respectivamente, con bajas intensidades luminosas (entre 0.2 y 5% de I) y relacionados en algunos casos con la nutriclina. En el Golfo de México y en el Mar Caribe se encuentra un tipo de perfil vertical característico de aguas oligotróficas tropicales, con bajas concentraciones de clorofila y con un máximo profundo localizado cerca de la nutriclina; la producción primaria es mínima. En cambio, en la plataforma de Yucatán el perfil se acerca hacia el extremo productivo de la estructura tropical típica, caracterizado por la alta concentración de clorofila y alta producción primaria así como por la presencia de una termoclina somera. La contribución del fitoplancton < 10 um a la biomasa pigmentaria es cuantitativamente más importante (50 a 100% del total) en aguas oligotróficas que en aguas eutróficas (20 a 67% de la clorofila a total)
Efecto antibacteriano del aceite esencial de orégano (Lippia berlandieri ) en bacterias patógenas de camarón Litopenaeus vannamei
Get PDFAn alternative for antibiotics use is the employment of vegetal oil extracts with unspecific antagonistic activity. In the present study, two fractions of essential oil from the oregano Lippia verlandieri, fraction high in thymol (FT) and fraction high in carvacrol (FC) were evaluated and compared to commercial antibiotics for the bacteria Aeromonas hydrophila, A. salmonicida, Pseudomonas putida, P. fluorescens, Vibrio mimicus, V. alginolyticus, V. fluvialis y V. vulnificus, isolated from shrimp Litopenaeus vannamei. The minimal inhibitory concentration (MIC) as well as the inhibition capacity in agar plates of these antimicrobials were evaluated and compared to commercial antibiotics. The survival of shrimp infected with V. alginolyticus and treated with the antimicrobials FT, FC and the antibiotic Enrofloxacine was also tested. The MIC of the FT and FC were from 50 to 100 µg/mL, the commercial antibiotic showed a MIC from 10 to 50 µg/mL. V. alginolyticus had the highest (p ? 0.05) sensitivity level (50 to 56 mm of inhibitory halo) with FC and Enrofloxacine. Shrimp survival was 70, 50 y 50% with application of FC, FT and Enrofloxacine, respectively. Both FT and FC fractions are able to control in vitro growth of pathogenic bacteria in shrimp. It was concluded that the fraction high in carvacrol from essential oregano oil, could be a viable alternative or a suplement to commercial antibiotics for the control of Vibrio spp. pathogens in penaeid shrimps.Una alternativa al uso de antibióticos comerciales son los extractos de aceites vegetales con actividad antimicrobiana no específica. En el presente estudio, se evaluó la concentración mínima inhibitoria (CMI) así como la capacidad de inhibición en placa del aceite esencial de orégano Lippia verlandieri, con fracción alta en timol (FT) y fracción alta en carvacrol (FC), comparados con antibióticos comerciales, para las bacterias Aeromonas hydrophila, A. salmonicida, Pseudomonas putida, P. fluorescens, Vibrio mimicus, V. alginolyticus, V. fluvialis y V. vulnificus, aisladas de camarón blanco Litopenaeus vannamei. Además, se determinó la supervivencia de camarones infectados con V. alginolyticus tratados con las fracciones FT, FC y Enrofloxacina. Las CMI de las FT y FC fueron de 50 a 100 µg/mL, mientras que el antibiótico comercial presentó una CMI de 10 a 50 µg/mL. La bacteria V. alginolyticus presentó el más alto (p ? 0.05) grado de sensibilidad (50 a 56 mm de halo de inhibición) con FC y Enrofloxacina. Por otro lado, la supervivencia de camarón fue de 70, 50 y 50% con la aplicación de FC, FT y Enrofloxacina, respectivamente. Ambas fracciones del extracto de aceite esencial de orégano tienen la capacidad de controlar el crecimiento in vitro de bacterias patógenas en camarón. Se concluye, que la fracción alta en carvacrol de aceite esencial de orégano es una alternativa viable o un complemento a los antibióticos comerciales para el control de Vibrio spp., patógenos en camarones peneidos
Crecimiento y producción de carpa común (Cyprinus carpio Linnaeus, 1758) durante la época de sequía y lluvias en un bordo del Estado de México, México
No full textThis paper describes the relationship between the environmental parameters (physical, chemical, absolute abundance of zooplankton and zoobenthos), and the absolute weight growth (CAP) of the carp (Cyprinus carpio), in a temporary pond of the State of México, Morelos, during the dry and wet season. The behavior of the system in both periods was influence by depth. During the dry season the water alkalinity, hardness, temperature and oxygen concentration increased, while transparency decreased. This season also registered the highest zooplankton and zoobenthos abundances, in this period, the most import parameter were, hardness and orthophosphate concentration, and in the wet season, hardness and pH. In the wet season, the environmental paramenters did not have values as drastic as those registered during the dry season, allowing the fishes to grow more. The yield in the wet season was 1,367% higher than during the dry season. During the dry season, the CAP was more related to the conductivity, pH and turbidity parameters, while in the dry season it was more related to the zoobenthos abundance and pH. The wet period is the stocking season recommended because is the most appropiate growth fish season.El presente trabajo da a conocer la relación entre los par´metros ambientales (físicos, químicos, abundancia absoluta de zooplancton y zoobentos) y el crecimiento absoluto en peso (CAP) de carpa común (Cyprinus carpio), en un bordo temporal del Estado de México, México, durnte las épocas de sequía y de lluvias. En ambas fases, la profundidad, influyó en el comportamiento del sistema. En la época de sequía se incrementan los valores de alcalinidad, dureza, temperatura, oxígeno y disminuye la turbiedad, además de presentar la myor abundancia de zooplancton y zoobentos en esta etapa los parámetros más importantes fueron, la dureza y la concentración de ortofosfatos. Para la época de lluvias los parámetros más importantes fueron la dureza y el pH en esta fase, los parámetros ambientales no alcanzaron valores extremos como durante la época de sequía, permitiendo que los peces crecieran más, obteniéndose una producción 1,367% mayor que durante la época de sequía. Durante la época de sequía el CAP se relacionó más con la conductividad pH y turbiedad y durante la época de lluvias con la abundancia del zoobentos y el pH. Se recomienda que los peces sean sembrados durante la época de lluvias por ser la más favorable para el crecimiento de las carpas
Macroalgae of Puerto Morelos Reef System, Mexican Caribbean
No full textA total of 113 species was found in Puerto Morelos reef system at four sampling sites in April 1995. Phycological differences were found between rear reef and lagoon as the Jaccard index accounts for only 28% of similarity between both habitats. It is evident that both habitats have different general conditions such as substrate and water motion, and they might some of the causes that produce quite different algal communities. A list of 245 species has been registered by 9 studies and our results for Puerto Moreos reef system. A wide difference in the number of reported species by different authors was found (158 to 23 species). Those results reflect different methods and sampling intensities used at each work. The species found in each sampling time can also be different because seasonal floristic cahnges and the occurence of environmental disturbances such as hurricanes. Floristic differences found between authors, as well as differences at habitat level suggest that a continuous study is need in all habitats of Puerto Morelos (rear and front reef, reef lagoon and deep waters) in order to have a better knowledge of this area