Hidrobiológica (E-Journal)
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Distribución de carbohidratos, carbono y nitrógeno orgánico en sedimentos de tres lagunas costeras del Golfo de México
No full textAn assessment of the concentrations of organic carbon and nitrogen in surface sediments, and carbohydrates in pore water was made in Pueblo Viejo, Tamiahua y Tampamachoco Lagoons in the Northern Coast of the Gulf of Mexico. During the period 1994 to 1995, the levels of organic carbon found were in descending order Tampamachoco Lagoon (1.59%), Tamiahua Lagoon (1.32%) and Pueblo Viejo Lagoon (1.03%). The carbohydrates concentrations in pore water followed a similar order to organic carbon, Tampamachoco (26.13 mg/l), Tamiahua (23.23 mg/l) and Pueblo Viejo Lagoon (19.74 mg/l). Tampamachoco Lagoon showed the highest concentration of organic nitrogen (171.91 mg/g), the Tamiahua Lagoon (134.94 mg/g) and Pueblo Viejo Lagoon (75.64 mg/g). The highest contents of organic fractions in the sediments and pore water were higher in the months associated to the rainy season, showing that the main contribution of the organic forms from three estuarine systems come from alloctonus sources and basically through fluvial drainage.En este estudio se determinaron las concentraciones tanto de carbono y nitrógeno orgánicos en sedimentos superficiales como de carbohidratos en el agua intersticial de las Lagunas Pueblo Viejo, Tamiahua y Tampamachoco en el noroeste del Golfo de México. En el período 1994-1995, los conetenidos de carbono orgánico siguieron el siguiente orden decreciente: laguna Tampamachoco (1.59%), laguna Tamiahua (1.32%) y laguna Pueblo Viejo (1.03%). Los carbohidratos presentaron el mismo comportamiento que el carbono orgánico, el mayor contenido lo tuvo la laguna Tampamachoco (26.13 mg/l), seguida por Tamiahua (23.23 mg/l) y por último Pueblo Viejo (19.74 mg/l). Las concentraciones de nitrógeno orgánico en orden decreciente fueron Tampamachoco (2406.74 mg/g), Tamiahua (1889.16 mg/g) y Pueblo Viejo (1058.96 mg/g). Los contenidos más altos de las fracciones orgánicas en el sedimento y en el agua intersticial fueron superiores en los mese asociados a la época de lluvias, indicando que el principal aporte de estas formas orgánicas a los tres sistemas estuarinos-lagunares proviene de entradas alóctonas y que llegan a las lagunas básicamente a través de los aportes fluviales
New records of brackish water Rotifera and Cladocera from Mexico
No full textZooplankton samples collected monthly from various parts of the brackishwater lagoon Macoacan in the State of Tabasco during the years 1995-1997 revealed the occurence of 37 rotifer species and two cladoceran species of which five rotifers viz. Platyias leloupi, Ploesoma hudsoni, Synchaeta bicornis, S. hyperborea and Trichocerca marina and one cladoceran viz. Moina minuta are new to Mexican fauna. The recorded species are ilustrated and aspects of their distribution are presented
Primer registro de corvineta ocelada Sciaenops ocellatus Linnaeus 1766 (Perciformes: Sciaenidae) en Campeche, México
Get PDFThe presence of Sciaenops ocellatus in Campeche Mexico, in catches of small scale fishermen in Isla Arena, Campeche City and Champotón is reported. The probable source of this introduction is attributed to escape of specimens from aquaculture floating cages located in nearby of Seybaplaya and Isla Arena, Campeche. Further research is required to assess the ecological impacts of this exotic species in the zone.Se reporta la presencia de Sciaenops ocellatus en Campeche, México en las capturas de pescadores artesanales en Isla Arena, en la ciudad de Campeche y en Champotón. La posible fuente de introducción es atribuida a escapes de especímenes de jaulas de cultivo en zonas cercanas a Seybaplaya e Isla Arena. Es necesario realizar más investigación para estimar los impactos ecológicos de esta especie exótica en la zona
Diatoms in the fish rearing center in Temascal, Oaxaca, México
No full textConsidering the importance and lack of studies of freshwater diatoms in Mexico, this research is a contribution to the knowledge of this group, particularly with respect to its taxonomic composition, distribution and abundance in the fish rearing ponds in Temascal, Oaxaca, Mexico. Samples from 14 ponds and two channels (one is supply channel and the other is for draining) were taken in March, 1991. On the whole, 41 samples were obtained which included plankton collected with a 54 µm mesh standard net an a van Dorn bottle, and benthic forms collected with a spatula or a siphon. The diatoms were cleaned and mounted in Naphrax resin. Relative abundance and frequency were computed counting all the organisms present in one ml of the original smaple, three times. A total of 31 species and varieties of seven families were identified, of which 98% belong to the Pennales order and 2% to the Centrales microcepahal var. microcephala, C. tumida var. tumida, Diploeneis puella var. puella, Gomphonema affine var. affine, G. angustatum var. angustatum, G. clavatum, Navicula notha var. notha y Pinnularia acrosphaeria var. acrosphaeria
Caracterización de la contaminación por metales pesados y reducción de capacidad de almacenamiento hidráulico por azolve de un embalse mexicano
Get PDFJosé Antonio Alzate is the first reservoir over the Lerma river and most of the sediments eroded in the upper Lerma river basin, an highly urbanized area, are deposited there. Alzate reservoir, accomplish functions for flood control and for water irrigation supply downstream. Recently a bathymetric study was carried out in order to know the new bottom reservoir profile. These levels were compared with those existing before the dam construction in 1959 and the sediment volume accumulation was obtained. Also a sampling of bottom sediments was obtained in order to make an analysis by X ray fluorescence spectrometry to define possible pollution by heavy metals. This paper, discuss the high reduction in reservoir storage capacity (close to 50%) and the sediment pollution which defines the environmental risks associated with their removal. Taking into account the low pollution concentrations of heavy metals measured, which do not exceed the standard international criteria for sediment use in agriculture and the relatively low volume of dredging lower than 65 000 m3 , it is recommended to dredge the area surrounding the intake structure for operation security, considering how important it is in the reservoir functioning.El embalse José Antonio Alzate es el primero sobre el curso del río Lerma y acumula los sedimentos erosionados de la cuenca del Curso Alto del río Lerma (CARL), un área densamente urbanizada. Desde el punto de vista hidráulico, dicho embalse cumple la función de control de avenidas y surte de agua a distritos de riego. La realización reciente de un estudio batimétrico del mismo permitió definir el perfil actual de fondo del terreno. Estos niveles se compararon con los originales (antes de su construcción en 1959) efectuando una estimación del volumen de azolve acumulado. Igualmente se llevó a cabo un muestreo de sedimentos de fondo para su posterior análisis por fluorescencia de rayos X con el fin de determinar su posible contaminación por metales pesados. En este artículo se discuten las implicaciones de la pérdida de capacidad de almacenamiento del embalse (cerca del 50%) y de la contaminación de sus sedimentos determinando los riesgos ambientales asociados por su remoción. Teniendo en cuenta los bajos índices de contaminación por metales pesados, los cuales no sobrepasaron los criterios internacionales para uso de sedimentos en agricultura, y del volumen a dragar inferior a los 65 000 m3 , se concluyó que es recomendable dragar la zona aledaña a la obra de toma para seguridad en la operación de esa estructura que es indispensable para cumplir con las funciones del embalse
Reproductive cycle of the Cortez angelfish Pomacanthus zonipectus (Gill, 1863) (Pomacanthidae) from the Gulf of California, Mexico.
Get PDFDifferent aspects of the reproductive biology of the Cortez angelfish Pomacanthus zonipectus were studied between July 1992, and June 1993 at Espíritu Santo Island, Baja California Sur, Mexico. The ovarian and testes development was analyzed using histological techniques. The reproductive cycle was determined and quantitatively analyzed. Five stages of gonadal development were established: resting, developing, ripe, spawning, and spent. P. zonipectus is a partial spawner that reproduces from June to November. The reproductive cycle of P. zonipectus shows a clear seasonally related with the water temperature, and gonadosomatic index. Gametogenesis started when water temperatures began to increase and continued during warmer months (26°C to 30°C). The interval of size at first sexual maturity was 210-220 mm total length
Los peces de la familia Atherinopsidae (Teleostei: Atheriniformes) de las lagunas costeras neutras e hipersalinas de México
Get PDFThe Order Atheriniformes includes six families, represented in Mexico by two of them: Atherinopsidae whose species are restricted to the freshwater highland lakes and shore estuarine species from both coasts of Mexico. Atherinidae is composed by only two marine shore species from the Gulf of Mexico. The new world silversides are located in the neritic zone and the epilimnion of lakes and rivers of highlands as well in the coastal plain. This group, comprises several marine species that goes into the continental waters and are frequently found in isohalyne and hypersaline coastal lagoons. These fish are interesting because their outstanding abundance in the aquatic ecosystems as well as their ecological role in low and medium trophic levels, besides being important commercially because they are part of some local or regional fisheries. Several taxonomic and biological information of each species is included. We can conclude that there are two taxonomic groups well defined: one in the Pacific and the other one in the Atlantic. From the ecological point of view, there are seven estenohalyn species and five eurihalyn that also have several salinity tolerance levels.La Serie Atherinomorpha está constituida por los órdenes Atheriniformes, Beloniformes y Cyprinodontiformes, que podría ser considerado como uno de los grupos filiales de la Serie Percomorpha. El Orden Atheriniformes contiene seis familias aunque solo está representado en México por dos: Atherinopsidae cuyas especies están restringidas a las aguas dulces del altiplano mexicano, y Atherinidae de las zonas neríticas y estuarino-lagunares del Golfo de México. Los aterinópsidos habitan la región epipelágica de la plataforma interna y del epilímnion de lagos y ríos tanto del altiplano como de la planicie costera. Dentro de ese grupo existen varias especies marinas que incursionan hacia las aguas continentales y se les encuentra con frecuencia en lagunas costeras neutras e hipersalinas. Estos peces son interesantes tanto desde el punto de vista ecológico porque constituyen una porción relevante de los ecosistemas acuáticos como forrajeros y consumidores de bajo a mediano nivel trófico, además de ser importantes desde el punto de vista comercial ya que forman parte de algunas pesquerías artesanales, locales o regionales. Se ofrece información taxonómica de varias especies pertenecientes a esta familia, recolectadas y registradas dentro de lagunas costeras neutras e hipersalinas de México. Se concluye con la existencia de dos grupos definidos en el Pacífico y en el Atlántico además de que, desde el punto de vista ecológico se pueden distinguir siete especies estenohalinas y cinco eurihalinas, que también manifiestan bastante tolerancia hacia las condiciones hipersalinas
Effect of the culture conditions on the growth and lipid contents of two strains of Nannochloris sp. to be used in aquaculture
No full texttwo strains of microalgae were obtained from the Texcoco lake, Mexico and San Pedrito Oasis Baja California Sur mexico, and named C1 and C2 respectively, previosly were selected as good candidates to improve the mass culture of a native strain of Brachionus plicatilis. In the laboratory, the isolates were purified and acclimated to growth under marine conditions at 35 ppt salinity and at 27-30ºC. Both strains were identified as Nannochloris sp. based primarily on their a, b chlorophyll and carotene contents and on light and transmission electron microscopy of the cell. Different culture conditions were tested in order to evaluate their effect on growth and lipid content. Differences in the response of both strains were found. Nannochloris sp strain C2 ws better adapted to different culture conditions (media, nitrogen concentrarion and culture vessel); this strain achieved higher growth and major lipid contents than strain C1. The conditions which improved the yield of both strains, are described. Also it was found that Nannochloris sp. strain C2 (isolated from a coastal oasis) has apparent advantages in yield over Nannochloris sp. strain C1 for use in aquaculture
Dinámica de las bacterias anaeróbicas en las fases terminales de la mineralización de la materia orgánica en el sedimento de los ecosistemas Carretas-Pereyra y Chantuto-Panzacola
Get PDFThe coastal sediments are important sites for the organic matter mineralization. In this ecosystems, where there is a constant input of sulfates, the sulfate reducing bacteria are the most important microorganisms implicated in the last anaerobic steps of mineralization; however the methanogenic bacteria are also important. There are several studies about the function of this anaerobic bacterial communities, mostly them in temperate regions. The aim of this study was investigate the seasonal and, spatial dynamics of sulfate reducing and, methanogenic bacteria in two coastal lagoons sediments located in Chiapas State. Sediment samples was collected at different months. The sulfate reducing and, methanogenic bacteria were evaluated with Most Probable Number technique using different substrates. Several physical and, chemical parameters was too measured. The sulfate reducing and, methanogenic bacteria were abundant in both coastal lagoons sediments. The bacterial density in the coastal lagoons studied was highest than the reported it in coastal and, freshwater sediments located in temperate regions. Seasonal and, spatial variations of the anaerobic bacterial populations were related with salinity, sulfate concentration and pH.La mineralización de la materia orgánica en los ecosistemas costeros, caracterizados por un aporte constante de sulfatos, se efectúa principalmente en la fase sedimentaria, siendo las bacterias anaeróbicas sulfatorreductoras los principales microorganismos implicados en las últimas fases de degradación. Sin embargo, las bacterias metanogénicas en estos ambientes también son importantes. Los estudios de las poblaciones bacterianas relacionadas con las fases terminales de la degradación anaeróbica de la materia orgánica, se han efectuado básicamente, en ecosistemas de zonas templadas. Con base en lo anterior, el objetivo del presente trabajo fue evaluar la dinámica espacial y temporal de las poblaciones bacterianas sulfatorreductoras y metanogénicas en el sedimento de dos ecosistemas estuarinolagunares localizados en el Estado de Chiapas. Las muestras de sedimento se colectaron en diferentes meses y la cuantificación de las bacterias sulfatorreductoras y metanogénicas, a partir de diferentes sustratos, se efectuó con la técnica del Número Más Probable. Asimismo, se analizaron diversas variables físicas y químicas en el sedimento y agua intersticial. Los resultados obtenidos indicaron que ambos grupos bacterianos fueron abundantes en el sedimento de las lagunas estudiadas, cuantificándose densidades superiores a las determinadas en sedimentos costeros y lacustres de zonas templadas. Las variaciones temporales y espaciales de la abundancia de estas poblaciones bacterianas se relacionó con el pH, la salinidad y el contenido de sulfatos