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8 resultados encontrados para: AUTOR: Cabanillas Terán, Nancy
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1.
- Artículo con arbitraje
ERISNet: deep neural network for Sargassum detection along the coastline of the Mexican Caribbean
Arellano Verdejo, Javier (autor) ; Lazcano Hernández, Hugo Enrique (autor) ; Cabanillas Terán, Nancy (autora) ;
Disponible en línea
Contenido en: PeerJ Volumen 7, número e6842 (2019), p. 1-19 ISSN: 2167-8359
PDF
Resumen en: Inglés |
Resumen en inglés

Recently, Caribbean coasts have experienced atypical massive arrivals of pelagic Sargassum with negative consequences both ecologically and economically. Based on deep learning techniques, this study proposes a novel algorithm for floating and accumulated pelagic Sargassum detection along the coastline of Quintana Roo, Mexico. Using convolutional and recurrent neural networks architectures, a deep neural network (named ERISNet) was designed specifically to detect these macroalgae along the coastline through remote sensing support. A new dataset which includes pixel values with and without Sargassum was built to train and test ERISNet. Aqua-MODIS imagery was used to build the dataset. After the learning process, the designed algorithm achievesa 90% of probability in its classification skills. ERISNet provides a novel insight to detect accurately algal blooms arrivals.


2.
Libro
The holocene and anthropocene environmental history of Mexico: a paleoecological approach on Mesoamerica / editors: Nuria Torrescano Valle, Gerald A. Islebe, Priyadarsi D. Roy
Torrescano Valle, Nuria (editora) ; Islebe, Gerald A. (editor) ; Roy, Priyadarsi Debajyoti (editor) ;
Cham, Switzerland : Springer International Publishing , c2019
Disponible en línea
Clasificación: EE/577 / H6
Bibliotecas: Campeche , San Cristóbal
Cerrar
SIBE Campeche
ECO040007071 (Disponible)
Disponibles para prestamo: 1
Cerrar
SIBE San Cristóbal
ECO010019867 (Disponible)
Disponibles para prestamo: 1
Resumen en español

This book provides essential information on Mexico’s Holocene and Anthropocene climate and vegetation history. Considering the geography of Mexico – which is home to a variety of climatic and environmental conditions, from desert and tropical to high mountain climates – this book focuses on its postglacial paleoecology and paleoclimatology. Further, it analyses human intervention since the middle Holocene as a major agent of environmental change. Offering a valuable tool for understanding past climate change and its relationship with present climate change, the book is a must-read for botanists, ecologists, palaeontologists and graduate students in related fields.

Índice

1 Introduction: The Holocene and Anthropocene Environmental History of Mexico
References
2 Paleoclimate of the Gulf of California (Northwestern Mexico) During the Last 2000 Years
Introduction
Regional Settings
Processes Responsible for the Sedimentation Cycle
Hydrological Processes Linked to Climate and Anthropogenic Changes
Integrated Water–Vertical Settling Studies in the Alfonso Basin
Climate Variations: Interannual, Centennial, and Millennial Scales
Centennial–Scale Variability
Climate Modeling
Conclusions
References
3 Holocene Hydroclimate of the Subtropical Mexico: A State of the Art
Introduction
Modern Climate
Register and Hypothesis
Vegetation Composition
Hydrological Variation and Climate Forcing
Conclusions
References
4 The Environment of Ancient Cloud Forests in the Mexican Pacific
The Mexican Pacific
The Past Environments in the Mexican Pacific
The Present Cloud Forest
The Ancient Cloud Forests
Methods
Results
Discussion
Conclusion
References
5 Sea Level Change and Its Influence on the Coastal Landscape in the Gulf of Mexico During the Holocene
Introduction
Vegetation Types in the Gulf of Mexico
Vegetation Response to Sea Level
Human Impact on Coastal Vegetation
Conclusion
References
6 Insights into the Holocene Environmental History of the Highlands of Central Mexico
Introduction
Central Mexico
Holocene Environment
References
7 Integration of Landscape Approaches for the Spatial Reconstruction of Vegetation
Introduction
Methods
Results
Discussion
References
8 Volcanic Activity in Mexico During the Holocene
Introduction
Distribution of Volcanoes in Mexico
Holocene Eruptions from Volcanoes in Mexico
Active Stratovolcanoes and Calderas
Monogenetic Volcanic Fields
Outlook of Holocene Volcanism
References


3.
- Capítulo de libro con arbitraje
*Solicítelo con su bibliotecario/a
Holocene paleoecology and paleoclimatology of South and Southeastern Mexico: a palynological and geospatial approach
Islebe, Gerald A. (autor) ; Carrillo Bastos, Alicia (autor) ; Aragón Moreno, Alejandro Antonio (autor) ; Valdéz Hernández, Mirna (autor) ; Torrescano Valle, Nuria (autor) ; Cabanillas Terán, Nancy (autora) ;
Disponible en línea
Contenido en: The holocene and anthropocene environmental history of Mexico: a paleoecological approach on Mesoamerica / editors: Nuria Torrescano Valle, Gerald A. Islebe, Priyadarsi D. Roy Cham, Switzerland : Springer International Publishing, 2019 páginas 195-207 ISBN:978-3-030-31718-8
Bibliotecas: Campeche , Chetumal , San Cristóbal
Cerrar
SIBE Campeche
59784-30 (Disponible)
Disponibles para prestamo: 1
Cerrar
SIBE Chetumal
59784-20 (Disponible)
Disponibles para prestamo: 1
Cerrar
SIBE San Cristóbal
59784-10 (Disponible)
Disponibles para prestamo: 1
Nota: Solicítelo con su bibliotecario/a
Resumen en español

Reconstruction of Holocene paleoecological conditions and paleoclimate of an area with high biological diversity and a variety of climatic conditions like southern and southeastern Mexico is complex. This region is characterized by vegetation types ranging from tropical forest to high mountain vegetation. Additionally, this region was inhabited by the ancient Maya culture, which shaped the landscape for several millennia. Previous paleoecological studies from this region were focused on the Maya culture-environment relationships, to decipher natural and human-induced deforestation. These studies also aimed to understand the effects of climatic regional forcing (El Niño-Southern Oscillation (ENSO), Intertropical Convergence Zone (ITCZ), and North Atlantic Oscillation (NAO) on the natural vegetation. In this chapter we review the paleoecological results and present a new geospatial approach to analyze past precipitation and tropical forest distribution of the Yucatán Peninsula from 1 AD to 1700 AD in 100-year intervals. The geospatial analysis revealed heterogeneity in spatial patterns of precipitation and tropical forest extension during the Late Preclassic, Terminal Classic, and Medieval Warm Period to Little Ice Age transition. The dry periods of the Middle and Late Holocene in the Yucatán Peninsula and southern Mexico can be chronologically placed in the following intervals: 4700–3600 cal year BP, 3400–2500 cal year BP, 2300–2100 cal year BP, 1900–1700 cal year BP, 1400–1300 cal year BP, 730 cal year BP, and 560 cal year BP. We conclude that this region requires additional studies with strong chronological framework due to its heterogeneous environmental conditions.


4.
- Artículo con arbitraje
PDF
Resumen en: Inglés |
Resumen en inglés

The arrival of large masses of drifting Sargassum since 2011 has caused changes in the natural dynamics of Caribbean coastal ecosystems. In the summer of 2015, unprecedented and massive mats of S. fluitans and S. natans have been observed throughout the Mexican Caribbean including exceptional accumulations ashore. This study uses stable isotopes to assess the impact of Sargassum blooms on the trophic dynamics of the Diadema antillarum sea urchin, a keystone herbivore on many Caribbean reefs. Bayesian models were used to estimate the variations in the relative proportions of carbon and nitrogen of assimilated algal resources. At three lagoon reef sites, the niche breadth of D. antillarum was analysed and compared under massive influx of drifting Sargassum spp. vs. no influx of Sargassum blooms. The effects of the leachates generated by the decomposition of Sargassum led to hypoxic conditions on these reefs and reduced the taxonomic diversity of macroalgal food sources available to D. antillarum. Our trophic data support the hypothesis that processes of assimilation of carbon and nitrogen were modified under Sargassum effect. Isotopic signatures of macroalgae associated with the reef sites exhibited significantly lower values of 15N altering the natural herbivory of D. antillarum. The Stable Isotopes Analysis in R (SIAR) indicated that, under the influence of Sargassum blooms, certain algal resources (Dictyota, Halimeda and Udotea) were more assimilated due to a reduction in available algal resources. Despite being an abundant available resource, pelagic Sargassum was a negligible contributor to sea urchin diet.

The Stable Isotope Bayesian Ellipses in R (SIBER) analysis displayed differences between sites, and suggests a reduction in trophic niche breadth, particularly in a protected reef lagoon. Our findings reveal that Sargassum blooms caused changes in trophic characteristics of D. antillarum with a negative impact by hypoxic conditions. These dynamics, coupled with the increase in organic matter in an oligotrophic system could lead to reduce coral reef ecosystem function.


5.
- Artículo con arbitraje
*Solicítelo con su bibliotecario/a
Succession and the relationship between vegetation and soil in the Marl Quarries of the Yucatan Peninsula, Mexico
Valdéz Hernández, Mirna (autora) ; Gil Medina, Rossana (autora) ; López Martínez, Jorge Omar (autor) ; Torrescano Valle, Nuria (autora) ; Cabanillas Terán, Nancy (autora) ; Islebe, Gerald A. (autor) ;
Contenido en: Forests Vol. 10, no. 116 (2019), p. 1-13 ISSN: 1999-4907
Nota: Solicítelo con su bibliotecario/a

6.
- Artículo con arbitraje
Understanding trophic relationships among Caribbean sea urchins
Rodríguez Barreras, Ruber (coaut.) ; Cuevas Viera, Elvira (coaut.) (1950-) ; Cabanillas Terán, Nancy (coaut.) ; Branoff, Benjamin (coaut.) ;
Contenido en: Revista de Biología Tropical Vol. 64, no. 2 (June 2016), p. 837-848 ISSN: 2215-2075
PDF
Resumen en: Español | Inglés |
Resumen en español

Relaciones tróficas entre los erizos de mar Caribe. Las especies Echinometra lucunter, Echinometra viridis, Lytechinus variegatus, Tripneustes ventricosus, and Diadema antillarum son los erizos de mar más comunes en los hábitat litorales del Caribe. Los erizos de mar T. ventricosus y L. variegatus habitan generalmente los pastos marinos mientras que las otras tres especies se encuentran asociadas a sustratos rocosos. Los hábitos alimentarios de estas especies han sido bien documentados y son reconocidas como herbívoros – omnívoros; sin embargo, pocas de estas especies han sido caracterizadas isotópicamente. Utilizamos los isótopos estables para caracterizar estas cinco especies de erizos y establecer las posiciones tróficas para las especies que cohabitan los mismos ecosistemas. También cuantificamos la contribución de los recursos alimentarios para E. lucunter. Los erizos T. ventricosus y D. antillarum mostraron los mayores valores de 15N y valores similares de &13C que variaron desde -11.6 ± 0.63 a -10.4 ± 0.99 %; donde el erizo E. lucunter mostró los valores más negativos con -15.40 ± 0.76 %. Las comunidades de algas no mostraron diferencias en valores promedio de &15N (F= 1.300, df= 3, p= 0.301), pero sí mostraron variaciones en los valores de &13C (F= 7.410, df= 3, p= 0.001). Los estudios de amplitud de elipses de nicho determinaron que las especies de los biotopos rocosos (D. antillarum, E. lucunter y E. viridis) no mostraron solapamiento de nicho. Similar resultado también se encontró en las especies de erizos que habitan en los pastos marinos.

Sin embargo, la distancia entre estas dos especies fue menor respecto a la distancia entre las especies de erizos que habitan en los sustratos rocosos. Nuestros resultados muestran que las especies que habitan en los pastos marinos mostraron valores más elevados de &13C en comparación con las especies de los sustratos rocosos. No se encontraron diferencias espaciales para E. lucunter &15N, pero sí en &13 C.. Los modelos de mezcla bayesianos demuestran la plasticidad alimentaria de E. lucunter, especie capaz de utilizar múltiples recursos algales dependiendo de la disponibilidad por sitio semejanzas en &15N entre D. antillarum y T. ventricosus parecen indicar similitudes tróficas entre ambas especies. Si bien T. ventricosus es reconocido como omnívoro, D. antillarum siempre ha sido considerado un herbívoro generalista. Finalmente, la falta de solapamiento entre las especies en los dos biotopos parece indicar una estrategia de partición de recursos para evitar la competencia de nicho entre especies concurrentes.

Resumen en inglés

The species Echinometra lucunter, Echinometra viridis, Lytechinus variegatus, Tripneustes ventricosus, and Diadema antillarum are the most common sea urchins of littoral habitats in the Caribbean. T. ventricosus and L. variegatus are associated with seagrass beds, while the other three species usually inhabit hardground substrates. Food preferences of these species are well documented and they are commonly accepted as being primarily herbivorous-omnivorous; nevertheless, few of them have previously been characterized isotopically. We used this approach for assessing the isotopic characterization of five echinoids. We established the trophic position of two groups of co-occurring species and quantified the contribution of food resources in the diet of Echinometra lucunter, considered the most common sea urchin in the Caribbean region. The species T. ventricosus and D. antillarum showed the highest values of δ15N. Sea urchins exhibited similar values of δ13C varying from -11.6 ± 0.63 to -10.4 ± 0.99%. The echinoid E. lucunter displayed the lowest values of carbon, from -15.40 ± 0.76%. Significant differences among species were found for δ15N and δ13C. Seaweed communities exhibited no differences among sites for overall δ15N (F= 1.300, df= 3, p= 0.301), but we found spatial differences for δ13C (F= 7.410, df= 3, p= 0.001).

The ellipse-based metrics of niche width analysis found that the hardground biotope species (D. antillarum, E. lucunter, and E. viridis) did not overlap each other. Similar results were obtained for the co-occurring species of the seagrass biotope; however, the distance between these species was closer than that of the hardground biotope species. The Bayesian mixing models run for E. lucunter at all four localities found differences in food resources contribution. The algae D. menstrualis, C. crassa and B. triquetrum dominated in CGD; whereas C. nitens, Gracilaria spp., and D. caribaea represented the main contributor algae to the diet of E. lucunter at LQY. In Culebra Island, no dominance of any particular algae was detected in TMD, where six of the eight species exhibited a similar contribution. Similarities in δ15N between D. antillarum and T. ventricosus may hint towards a similar trophic level for these species, although T. ventricosus is widely accepted as an omnivore, while D. antillarum is considered a generalist herbivore. The lack of overlap among species in the two biotopes seems to indicate a resource partitioning strategy to avoid niche competition among co-occurring species.


7.
- Artículo con arbitraje
Gender-related differences in the apparent timing of skeletal density bands in the reef-building coral Siderastrea siderea
Carricart Ganivet, Juan P. ; Vásquez Bedoya, L. F. (caout.) ; Cabanillas Terán, Nancy (coaut.) ; Blanchon, Paul (coaut.) ;
Contenido en: Coral Reefs Vol. 32, no. 3 (September 2013), p. 769-777 ISSN: 0722-4028
Resumen en: Inglés |
Resumen en inglés

Density banding in skeletons of reef-building corals is a valuable source of proxy environmental data. However, skeletal growth strategy has a significant impact on the apparent timing of density-band formation. Some corals employ a strategy where the tissue occupies previously formed skeleton during as the new band forms, which leads to differences between the actual and apparent band timing. To investigate this effect, we collected cores from female and male colonies of Siderastrea siderea and report tissue thicknesses and density-related growth parameters over a 17-yr interval. Correlating these results with monthly sea surface temperature (SST) shows that maximum skeletal density in the female coincides with low winter SSTs, whereas in the male, it coincides with high summer SSTs. Furthermore, maximum skeletal densities in the female coincide with peak Sr/Ca values, whereas in the male, they coincide with low Sr/Ca values. Both results indicate a 6-month difference in the apparent timing of density-band formation between genders. Examination of skeletal extension rates also show that the male has thicker tissue and extends faster, whereas the female has thinner tissue and a denser skeleton—but both calcify at the same rate.

The correlation between extension and calcification, combined with the fact that density banding arises from thickening of the skeleton throughout the depth reached by the tissue layer, implies that S. siderea has the same growth strategy as massive Porites, investing its calcification resources into linear extension. In addition, differences in tissue thicknesses suggest that females offset the greater energy requirements of gamete production by generating less tissue, resulting in differences in the apparent timing of density-band formation. Such gender-related offsets may be common in other corals and require that environmental reconstructions be made from sexed colonies and that, in fossil corals where sex cannot be determined, reconstructions must be duplicated in different colonies.


8.
- Artículo con arbitraje
Sensitivity of calcification to thermal stress varies among genera of massive reef-building corals
Carricart Ganivet, Juan P. ; Cabanillas Terán, Nancy (coaut.) ; Cruz Ortega, Agustín Israel (coaut.) ; Blanchon, Paul (coaut.) ;
Contenido en: PLoS ONE Vol. 7, no. 3, e32859 (March 2012), p. 1-8 ISSN: 1932-6203
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Resumen en: Inglés |
Resumen en inglés

Reductions in calcification in reef-building corals occur when thermal conditions are suboptimal, but it is unclear how they vary between genera in response to the same thermal stress event. Using densitometry techniques, we investigate reductions in the calcification rate of massive Porites spp. from the Great Barrier Reef (GBR), and P. astreoides, Montastraea faveolata, and M. franksi from the Mesoamerican Barrier Reef (MBR), and correlate them to thermal stress associated with ocean warming. Results show that Porites spp. are more sensitive to increasing temperature than Montastraea, with calcification rates decreasing by 0.40 g cm−2 year−1 in Porites spp. and 0.12 g cm−2 year−1 in Montastraea spp. for each 1°C increase. Under similar warming trends, the predicted calcification rates at 2100 are close to zero in Porites spp. and reduced by 40% in Montastraea spp. However, these predictions do not account for ocean acidification. Although yearly mean aragonite saturation (Ωar) at MBR sites has recently decreased, only P. astreoides at Chinchorro showed a reduction in calcification. In corals at the other sites calcification did not change, indicating there was no widespread effect of Ωar changes on coral calcification rate in the MBR.

Even in the absence of ocean acidification, differential reductions in calcification between Porites spp. and Montastraea spp. associated with warming might be expected to have significant ecological repercussions. For instance, Porites spp. invest increased calcification in extension, and under warming scenarios it may reduce their ability to compete for space. As a consequence, shifts in taxonomic composition would be expected in Indo-Pacific reefs with uncertain repercussions for biodiversity. By contrast, Montastraea spp. use their increased calcification resources to construct denser skeletons. Reductions in calcification would therefore make them more susceptible to both physical and biological breakdown, seriously affecting ecosystem function in Atlantic reefs.