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4 resultados encontrados para: TEMA: Bahía de La Paz (Baja California Sur, México)
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1.
- Artículo con arbitraje
*Solicítelo con su bibliotecario/a
Evidence of intense suboxia and anoxia in a tropical bay of the Gulf of California
Sánchez, Alberto (autor) ; Rodríguez Figueroa, Griselda Margarita (autora) ; Shumilin, Evgueni N. (coaut.) ; Ortíz Hernández, Ma. Concepción (autora) ;
Contenido en: Continental Shelf Research Vol. 168 (September 2018), p. 21-27 ISSN: 0278-4343
Nota: Solicítelo con su bibliotecario/a
Resumen en: Inglés |
Resumen en inglés

The expansion of the upper boundary of the oxygen minimum zone (OMZ) has been associated with the low solubility of oxygen in the surface ocean due to global warming in tropical regions. However, sedimentary records of δ15N of sinking particulate organic matter and sediments suggest that oxygen solubility is controlled by oceanographic forcing in the tropical equatorial region. To determine the intensification of the OMZ within its upper border, δ15N analysis of the organic matter in superficial sediments of La Paz Bay was carried out. In the present work, 115 samples of superficial sediment were collected in the interval of 2–407 m depth in La Paz Bay. The surface sediments were analysed for the nitrogen isotopic composition of their organic matter. Hypoxia conditions (< 60 μM) at 100 m to depth suggest an intense denitrification of the water column that it was reflected in the sedimentary δ15N. The δ15N of the organic matter is 1.5‰ greater in the bay than in the mouth of the Gulf of California, indicating greater denitrification towards the interior of the bay with respect to the gulf mouth. The intense suboxia/anoxia conditions have been maintained due to a well-mixed water column that promotes exported productivity in La Paz Bay.


2.
- Artículo con arbitraje
*Solicítelo con su bibliotecario/a
Variation in isotopic trophic structure and fish diversity in mangrove systems subject to different levels of habitat modification in the Gulf of California, Mexico
López Rasgado, Francisco Javier ; Lluch Cota, Salvador E. (coaut.) ; Balart, Eduardo F. (coaut.) ; Herzka, Sharon Z. (coaut.) ;
Contenido en: Bulletin of Marine Science Vol. 92, no. 4 (October 2016), p. 399-422 ISSN: 0007-4977
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Resumen en: Inglés |
Resumen en inglés

Anthropogenic modification of mangrove systems can lead to decreased habitat quality, potentially affecting food web structure and ecosystem function. Based on carbon and nitrogen stable isotopes, we evaluated the trophic structure of the fish communities from three mangrove systems in southern Baja California, Mexico, subject to varying levels of habitat modification. We hypothesized that anthropogenic habitat modification leads to differences in niche space (and hence trophic structure). We applied a Bayesian approach to the calculation of community level isotope-based metrics of functional trophic structure and compared the results to a structural (Shannon-Wiener) index of diversity. Frequency distributions of stable isotope ratios revealed differences between the highly modified mangrove system and those with limited or no habitat modification. Comparison of the isotopic composition of the dominant fish species sampled in summer and winter indicated limited seasonal differences in this arid region. However, isotope-derived metrics of niche space were evaluated in the most highly modified mangrove system, suggesting a greater complexity in nutrient and primary production sources, a higher level of dietary specialization, and low functional redundancy. Fishes from the most pristine mangrove system exhibited highest diversity, a more limited range of isotopic values, and smaller measures of isotopic niche space, indicative of higher trophic redundancy. Comparison of the standardized (baseline-controlled) species-specific isotope ratios indicated that in 37% of cases isotopic differences persisted, further supporting our interpretation of variations in trophic structure. This research highlights that mangrove habitat modification has a marked influence on functional trophic diversity, as well as the fish community structure.


3.
- Artículo con arbitraje
Redescriptions of Nereis oligohalina (Rioja, 1946) and N. garwoodi González-Escalante & Salazar-Vallejo, 2003 and description of N. confusa sp. n. (Annelida, Nereididae)
Conde Vela, Víctor Manuel ; Salazar Vallejo, Sergio I. (coaut.) ;
Contenido en: ZooKeys No. 518 (August 2015), p. 15-49 ISSN: 1313-2989
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Resumen en: Inglés |
Resumen en inglés

Type material of several polychaete species described by Enrique Rioja from Mexican coasts are lost, and the current status of some species is doubtful. Nereis oligohalina (Rioja, 1946) was described from the Gulf of Mexico, but it has been considered a junior synonym of N. occidentalis Hartman, 1945, or regarded as a distinct species with an amphiamerican distribution. On the other hand, N. garwoodi González-Escalante & Salazar-Vallejo, 2003, described from Chetumal Bay, Caribbean coasts, could be confused with N. oligohalina. In order to clarify these uncertainties, N. oligohalina is redescribed based on specimens from the Mexican Gulf of Mexico, including a proposed neotype; further, N. garwoodi is redescribed including the selection of lectotype and paralectotypes, and N. confusa sp. n. is described with material from the Gulf of California. A key for the identification of similar species and some comments about speciation in nereidid polychaetes are also included.


4.
Artículo
*En hemeroteca, SIBE-Chetumal, SIBE-San Cristóbal
Simbiosis entre Collisella spp. (Gastropoda) y Zygantroplana ups (Platyhelminthes: turbellaria) en el Golfo de California, México
Salazar Vallejo, Sergio I. (autor) ; González Vallejo, Norma Emilia (autora) ;
Disponible en línea
Clasificación: AR/594.3 / S2/2
Contenido en: Revista de Biología Tropical Vol. 44, no. 1 (abril 1996), p. 97-105 ISSN: 0034-7744
Bibliotecas: Chetumal , San Cristóbal
Cerrar
SIBE Chetumal
19822-40 (Disponible) , ECO030000418 (Disponible)
Disponibles para prestamo: 2
Cerrar
SIBE San Cristóbal
ECO010019127 (Disponible) , 19822-30 (Disponible) , SER001020 (Disponible)
Disponibles para prestamo: 3
Nota: En hemeroteca, SIBE-Chetumal, SIBE-San Cristóbal
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Resumen en: Español | Inglés |
Resumen en español

La planaria Zygantroplana ups Marcus & Harry fue originalmente descrita como simbionte de la ostra Myrakeena angelica (Rochebrune) de Baja California (BC), Mexico. Aquí se le registra en asociación con varias especies de lapa (Collisella spp.) en Bahía de la Paz, BC Sur. La ralación no es taxonómicamente específica, y no hubo asociación entre tamaño corporal de la lapa y el número de planarias, pero las planarias más grandes mostraron una mayor tasa de incidencia. A mayor densidad de lapas hubo menos incidencia de las planarias. El peso de las lapas no se vio afectado por los tasas de incidencia de planarias. Esta asociaci6n puede ser casual más que el fruto de selección natural específica.

Resumen en inglés

The flatworm Zygantroplana ups Marcus & Harry was originally described as a symbiont of the oyster Myrakeena angelica (Rochebrune) from Baja Califomia (BC), Mexico. Here it is recorded in association with several limpet species (Collisella spp.) in Bahía de la Paz, southem BC. The relationship is not species-specific, and there was no association bctween Iimpet body sire and the number of planarians, bu! larger limpets had a greater incidence rateo Si tes with higher limpet densities had lower planarian incidence. Limpet weight was no! affected by the levels of planarian occurrence found here. Ther association may reflect ehance ratner than natural selection.