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74 resultados encontrados para: TEMA: Propiedades fisicoquímicas
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1.
Artículo
Effects of plastic mulch film residues on wheat rhizosphere and soil properties
Qi, Yueling (autora) ; Ossowicki, Adam (autor) ; Yang, Xiaomei (autora) ; Huerta Lwanga, Esperanza (autora) ; Dini Andreote, Francisco (autor) ; Geissen Geissen, Violette (autora) ; Garbeva, Paolina (autora) ;
Contenido en: Journal of Hazardous Materials Vol. 387, 121711 (2020), p. 1-7 ISSN: 0304-3894
PDF
Resumen en: Inglés |
Resumen en inglés

Plastic residues could accumulate in soils as a consequence of using plastic mulching, which results in a serious environmental concern for agroecosystems. As an alternative, biodegradable plastic films stand as promising products to minimize plastic debris accumulation and reduce soil pollution. However, the effects of residues from traditional and biodegradable plastic films on the soil-plant system are not well studied. In this study, we used a controlled pot experiment to investigate the effects of macro- and micro- sized residues of low-density polyethylene and biodegradable plastic mulch films on the rhizosphere bacterial communities, rhizosphere volatile profiles and soil chemical properties. Interestingly, we identified significant effects of biodegradable plastic residues on the rhizosphere bacterial communities and on the blend of volatiles emitted in the rhizosphere. For example, in treatments with biodegradable plastics, bacteria genera like Bacillus and Variovorax were present in higher relative abundances and volatile compounds like dodecanal were exclusively produced in treatment with biodegradable microplastics. Furthermore, significant differences in soil pH, electrical conductivity and C:N ratio were observed across treatments. Our study provides evidence for both biotic and abiotic impacts of plastic residues on the soil-plant system, suggesting the urgent need for more research examining their environmental impacts on agroecosystems.


2.
Artículo
PDF PDF
Resumen en: Español | Inglés |
Resumen en español

Las características de los humedales costeros son resultado de las interacciones hidrogeomorfológicas entre el continente y el océano, que causan un gradiente ambiental, que resulta en diferentes tipos de vegetación como manglares, popales, tulares, selvas y palmares inundables. Objetivo: Caracterizar las variables del hidroperiodo y fisicoquímicas del agua y suelo para determinar la relación que existe en el patrón de distribución de la vegetación en el Sistema de Humedales El Castaño (SHC). Metodología: Se establecieron 11 unidades de muestreo (UM) permanentes por estrato definidos: cinco en el manglar, dos en selvas inundables, dos en tular y dos en pastizal inundable. De mayo 2016 a octubre 2017 se caracterizó la vegetación y se muestreó mensualmente los niveles de inundación y parámetros fisicoquímicos del agua (superficial, intersticial y subterránea): salinidad, conductividad y pH; y el suelo: densidad aparente, porcentaje de humedad y potencial redox. Resultados: El manglar es el más cercano al mar, tiene la menor diversidad (H:1.66) y especies registradas (14), está dominado por Laguncularia racemosa y Rhizophora mangle y tiene los valores más altos de salinidad intersticial y subterránea, mayores a 10.8 ups, se mantiene inundado de 4 a 12 meses, su potencial redox es de 14.57 mV. Seguido está el manglar, tierra adentro, se ubican los remanentes de la selva inundable, (H:2.18 y 18 especies), dominada por Pachira aquatica, la salinidad intersticial y subterránea de 4.95 ups, permanece inundada de 0 a 6 meses y el potencial redox es de 119.07 mV. El tular, después de la selva, (H:1.92 y 16 especies), dominado por Typha domingensis, salinidad intersticial y subterránea de 6.1 ups, el tiempo de inundación es de 5 a 8 meses y potencial redox es de 125.9 mV.

El pastizal inundable, con menor influencia marina, es un humedal herbáceo modificado para uso ganadero, presentó los valores más altos de diversidad (H:3.44 y 50 especies), Paspalum conjugatum es la especie dominante, la salinidad intersticial y subterránea es menor a 0.5 ups, se mantiene inundado de 5 a 9 meses y el potencial redox es de 151.23 mV. Conclusiones: En cada tipo de vegetación, la estructura, composición y diversidad es diferente, con un alto recambio de especies que indica un gradiente definido por la salinidad.

Resumen en inglés

Distribution patterns and vegetation structure in the coastal wetland gradient in the Castaño, Chiapas, Mexico. Introduction: The characteristics of coastal wetlands are the result of hydrogeomorphological interactions between the continent and the ocean, which cause an environmental gradient, hat results in different vegetation types such as mangroves, freshwater marshes, swamp forests and palm swamps. Objective: To characterize the hydroperiod and physicochemical variables of water and soil and their effect on the distribution of vegetation in the Sistema de Humedales El Castaño. Methods: A total of 11 permanent sampling units (UM) were established by defined strata: five in the mangrove, two in swamp forest, two in freshwater marshes and two in the flooded pasture. From May 2016 to October 2017 the vegetation was characterized and the water levels and physicochemical parameters (superficial, interstitial and groundwater) were sampled monthly for: salinity, and pH; and the soil for: bulk density, humidity percentage, and redox potential.

Results: Mangroves are the closest to the sea, have the lowest diversity (H: 1.66) and species richness (14), they are dominated by Laguncularia racemosa and Rhizophora mangle, have the highest values of interstitial and groundwater salinity, (> 10.8 ups), remain flooded for 4 to 12 months per year, and have a redox potential of 14.57 mV. Immediately, inland, there are remnants of the swamp forests (H: 2.18 and 18 species), dominated by Pachira aquatica , with 5 ups interstitial and groundwater salinity, flooded from 0 to 6 months per year, with a redox potential of 119.07 mV. These forests are followed inland by freshwater marshes (H: 1.92 and 16 species), dominated by Typha domingensis with 6.1 ups interstitial and groundwater salinity, flooded for 5 to 8 months per year and a redox potential of 125.9 mV. Finally, furthest inland is the flooded pasture, a modified herbaceous wetland for cattle grazing (H: 3.44 and 50 species) dominated by Paspalum conjugatum , where interstitial and groundwater salinity is less than 0.5 ups, it stays flooded for 5 to 9 months and the redox potential is 151.23 mV. Conclusions: In each type of vegetation, the structure, composition, and diversity are different, with a high turnover of species that indicates a gradient defined by salinity. The vegetation in the SHC follows the patterns of typical organization of the tropical coastal wetlands, mangroves, swamp forests and herbaceous wetlands, in this case the freshwater marshes and flooded pastures. The factor that define the distribution of the vegetation is the salinity and the gradient that is observed are a function of the hydrological dynamics that depends on the mixing of marine and freshwater.


3.
Artículo
*Solicítelo con su bibliotecario/a
Spatial and temporal habitat use by Penaeid shrimp (Decapoda: Penaeidae) in a coastal lagoon of the southwestern Gulf of Mexico
Torres Velázquez, Jony Ramiro (autor) ; Sánchez Martínez, Alberto de Jesús (autor) ; Barba Macías, Everardo (autor) ;
Contenido en: Regional Studies in Marine Science Vol. 34, article number 101052 (February 2020), p. 1-12 ISSN: 2352-4855
Nota: Solicítelo con su bibliotecario/a
Resumen en: Inglés |
Resumen en inglés

Knowledge of the environmental factors that influence the spatial–temporal densities of penaeid shrimp in Mecoacán Lagoon is important for understanding their relationship with the presence (migration) and estuarine habitat preferences. In the present study, the relationships between the physical–chemical components of water and sediments and the population dynamics of penaeid shrimp in Mecoacán Lagoon were evaluated according to a spatial–temporal and multihabitat approach. In six monitoring sites (Boca, Cerros, Mojarrero, Aspoquero Arrastradero and Pajaral), the density and biomass of shrimp were determined from November 2014 to October 2015 based on monthly captures with two nets (seine and renfro) in three habitats: mangrove, soft substrates without vegetation, and submerged aquatic vegetation that corresponds to seagrasses (seagrasses was registered only in Bocaand Cerros). The maximum salinity was found in Boca (23±2.6PSU), with pH values ranging from 7.9±0.1 to 8.3±0.2, and the maximum dissolved oxygen was found in Cerros (6.6±0.5mg/L). The average texture of sediments was 62±3.5% sand, 24±2.4% silt, and 14±1.2% clay.

The highest organic matter (7.8±1.2%) and nitrogen (875mg/kg) contents were recorded in Pajaral. A total of 5,085 penaeid shrimp were captured (seine 77% and renfro 33%), including the species Farfantepenaeus aztecus (Ives) (1,774 ind.), Farfantepenaeus duorarum (Burkenroad) (1,559 ind.), and Litopenaeus setiferus (L.) (1,752 ind.), with a total wet weight of 2,419 g. The spatial segregation patterns of penaeid shrimp suggest that their temporal distribution and habitat preferences are important for reducing interspecific competition. Salinity, dissolved oxygen, organic matter content, and sediment type were the factors that most influenced the spatial–temporal differences in the density and biomass of the penaeid shrimp among sites. Knowledge of the habitat distribution and preferences of key estuarine species such as penaeid shrimp can be used as an informational baseline for evaluating future environmental scenarios and modeling species distribution along the estuarine gradient.


4.
Artículo
Resumen en: Inglés |
Resumen en inglés

In this study, bone char (BC) from pleco fish (Pterygoplichthys spp.) was synthesized, and their textural and physicochemical properties, as well as its adsorption capacity towards fluoride and Cd(II) from single and binary aqueous solutions, were determined. The results showed that the properties of the BCs were independent of the type of bone used and the surface areas were close to 110 m² g−¹. The effect of solution pH revealed that the adsorption capacity of BC towards fluoride from water raised by decreasing the solution pH. This trend was attributed to the electrostatic interaction between the positively charged surface and the fluoride in aqueous solution. On the contrary, the capacity of BC for adsorbing Cd(II) was enhanced by increasing the solution pH, indicating that electrostatic interactions were also essential but with a contrary effect in comparison with fluoride adsorption due to the negatively charged surface at pH above the point zero charge (pHPZC = 8.16). The experimental data for binary adsorption of fluoride and Cd(II) were interpreted satisfactorily using the modified Freundlich multicomponent isotherm (EFMI), and the experimental data revealed that Cd(II) have an antagonistic effect on the adsorption of fluoride, whereas the presence of fluoride does not affect the capacity of BC for adsorbing Cd(II). Thermogravimetric, XRD diffraction and IR spectroscopy analysis corroborated that the adsorption of fluoride in BC is due to electrostatic attractions, ion exchange or chemisorption and physisorption. Besides, the removal of Cd(II) occurs by physical adsorption and ion exchange. It was concluded that BC is an alternative material for the removal of fluoride and Cd(II) from aqueous solutions, and it is a possible application for using the bones of this invasive fish species.


5.
Tesis - Maestría
Determinación de la biomasa y contenido de carbono en raíces de un bosque de mangle en la Reserva de la Biosfera La Encrucijada, Chiapas / Mitzi Estefanía Gutiérrez Hernández
Gutiérrez Hernández, Mitzi Estefanía (autora) ; Tovilla Hernández, Cristian (director) ; De Jesús Navarrete, Alberto (asesor) ; Torrescano Valle, Nuria (asesora) ;
Tapachula, Chiapas, México : El Colegio de la Frontera Sur , 2019
Clasificación: TE/583.42097275 / G8
Bibliotecas: Tapachula
Cerrar
SIBE Tapachula
ECO020013820 (Disponible)
Disponibles para prestamo: 1
Resumen en español

Los manglares proporcionan diversos servicios ambientales como capturar y almacenar por tiempos prolongados cantidades elevadas de carbono. Esto los ha posicionado como una alternativa para mitigar el proceso del cambio climático. El objetivo del presente estudio fue cuantificar la biomasa, productividad y contenido de carbono en raíces subterráneas en un bosque de mangle en la zona núcleo de la Reserva La Encrucijada. Se obtuvieron 160 núcleos mediante el método de colecta instantánea y 160 costales por el método de producción de raíces durante 6 y 12 meses. También se determinaron los parámetros fisicoquímicos del agua en el sitio y se obtuvieron muestras de suelo. Cada núcleo y costal fue separado en tres estratos para cuantificar las raíces vivas, posteriormente estas fueron clasificadas por grosor y se determinó el peso seco para el cálculo de biomasa, productividad y carbono. Los contenidos de biomasa, productividad de raíces y contenido de carbono variaron (p ≤0.01) de acuerdo con el estrato, conglomerado y grosor de raíz. Los mayores contenidos se determinaron en el C-3 (60 cm de profundidad) y C4-6 (90 cm de profundidad). Estos variaron con base en la profundidad, con mayores contenidos en los estratos 0-20 y 0-30 cm y menores en los estratos 41-60 y 61-90 cm. Los parámetros fisicoquímicos del agua no presentaron relación con el estrato y la biomasa, de igual forma los elementos determinados en suelo fueron similares en todos los conglomerados.

Durante el estudio, el sitio presentó ciertas condiciones homogéneas que dan pauta a contenidos similares de biomasa y producción de raíces en todos los conglomerados, por lo que si se alterara drásticamente algún parámetro en agua o en suelo alteraría el equilibrio de la producción de raíces y por lo consiguiente el almacén de carbono presente en el sitio. Sin embargo, es necesario conocer la biomasa área y relacionarla con los datos obtenidos para poder confirmar la homogeneidad del sitio.

Índice

Resumen
I. Introducción
II. Marco Teórico
2.1 Humedales
2.2 Manglares
2.2.1 Rhizophora mangle L.
2.2.2 Laguncularia racemosa (L.) Gaertn
2.2.3 Avicennia germinans L.
2.3 Hábitat
2.3.1 Características del suelo
2.3.2 Características fisicoquímicas del agua
2.3.3 Tipo fisonómico de bosque
2.4 Biomasa
2.5 Carbono
2.6 Importancia
2.7 Vulnerabilidad
III. Justificación
IV. Pregunta de Investigación
V. Hipótesis
VI. Objetivos
6.1 Objetivo general
6.2 Objetivos específicos
VII. Materiales y Métodos
7.1 Área de estudio
7.2 Colecta instantánea
7.3 Producción de raíces
7.4 Procesamiento de raíces
7.5 Parámetros fisicoquímicos del agua y profundidad del manto freático
7.6 Análisis de suelo
7.7 Análisis de datos
VIII. Resultados
8.1 Colecta instantánea
8.2 Producción de raíces
8.3 Biomasa de raíces por grosor
8.3.1 Raíces finas
8.3.2 Raíces medianas
8.3.3 Raíces gruesas
8.4 Productividad de raíces por grosor
8.4.1 Raíces finas
8.4.2 Raíces medianas
8.4.3 Raíces gruesas
8.5 Parámetros fisicoquímicos del agua
8.6 Profundidad del manto freático
8.7 Análisis de suelo
IX. Discusión
9.1 Biomasa de raíces
9.2 Productividad de raíces
9.3 Carbono en raíces
9.4 Parámetros fisicoquímicos del agua
9.5 Profundidad del manto freático
9.6 Análisis de suelo
X. Conclusiones
XI. Literatura Citada

XII. Anexos. Anexo 1. Contenido de biomasa aportada por método, grosor, estrato y conglomerado (Medias ± error estándar de Mg ha-¹ y Mg ha-¹ año-¹)
Anexo 2. Contenido de carbono cuantificado por grosor, método, estrato y conglomerado (Medias ± error estándar de Mg C ha-¹ y Mg C ha-¹ año-¹)
Anexo 4. Profundidad del manto freático (Medias ± error estándar)
Anexo 5. Resultados de los análisis de suelo del sitio de estudio (Los resultados están expresados en %)
Anexo 6. Resultados de los análisis de suelo del sitio de estudio (Los resultados están expresados en ppm)
Anexo 7. Artículo enviado a la Revista Madera y Bosques


6.
Artículo
Effect of thermal treatment on the extraction efficiency, physicochemical quality of Jatropha curcas oil, and biological quality of its proteins
Sánchez Chino, Xariss Miryam (autora) ; Corzo Ríos, L. J. (autor) ; Martínez Herrera, J (autor) ; Cardador Martínez, A. (autor) ; Jiménez Martínez, C (autor) ;
Disponible en línea
Contenido en: Journal of Food Science & Technology Volumen 56, número 3 (March 2019) , p. 1567–1574 ISSN: 0975-8402
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Resumen en: Inglés |
Resumen en inglés

Jatropha curcas seeds are an important source of oil (5-60%), used to obtain biodiesel. The generated residual paste has a high concentration of proteins (50-55%); however, the seeds contain non-nutritional factors that limit their use. The objective of this work was to analyze the effect on the physicochemical properties of the oil obtained from J. curcas seeds subjected to different thermal treatments and to evaluate the biological quality of the proteins contained in the residual cake. The best extraction of oil (95%) was obtained after 10 h from roasted or boiled seeds. In the oil from roasted samples, the acid index increased significantly (p ≤ 0.05) with respect to the untreated sample, whereas the iodine index increased significantly (p ≤ 0.05) in the oil extracted from the boiled samples. With respect to the proximal chemical composition of the flour, roasting and boiling treatments allowed for greater oil extraction (97 and 92%), achieving, in turn, a higher content of proteins (59.56 and 58.5 g/100 g) and fiber (6.67 and 6.67 g/100 g), and lower activity of trypsin inhibitors (45 and 38%) and phytates (63 and 72%), respectively. According to the in vivo biological quality test, conducted on Wistar rats, the thermal treatments applied to the seeds improved digestibility (> 70%) and the protein efficiency index (PER). The thermal treatment allowed extracting more efficiently the oil and improved the quality of the proteins present in the residual paste.


7.
Artículo
*Solicítelo con su bibliotecario/a
Production and biomass of mangrove roots in relation to hydroperiod and physico-chemical properties of sediment and water in the Mecoacan Lagoon, Gulf of Mexico
Torres Velázquez, Jony Ramiro ; Barba Macías, Everardo (coaut.) ; Choix, Francisco J. (coaut.) ;
Contenido en: Wetlands Ecology and Management Vol. 27, no 2–3 (June 2019), p. 427–442 ISSN: 1572-9834
Bibliotecas: Chetumal
Cerrar
SIBE Chetumal
59486-10 (Disponible)
Disponibles para prestamo: 1
Nota: Solicítelo con su bibliotecario/a
Resumen en: Inglés |
Resumen en inglés

Production and biomass information of roots is valuable for understanding the ecological process within mangroves. In this study, the production, biomass, turnover rate, and longevity of underground roots of mangrove (Rhizophora mangle L., Laguncularia racemosa L. Gaertn, and Avicennia germinans L. Stearn), as well as the density and biomass of pneumatophores was evaluated in relation to hydroperiod and physico-chemical properties of substrate and water in the Mecoacan Lagoon, Gulf of Mexico. Root extraction was performed in order to measure the biomass and production of roots by in-growth core technique; whilst the hydroperiod and physico-chemical parameters in water were determined using piezometers. The study was conducted from September 2016 to August 2017. A total root biomass of 23.7 tonDw ha−¹ (subterranean roots + pneumatophores) was weighing; the large roots showed the highest biomass weighing 1532 ± 254 gDw m−²; followed by the medium roots (189 ± 30 gDw m−²) and fine roots (194 ± 27 g Dw m−²). The average total production was 0.41 ± 0.05 g m−² day−¹, an average turnover rate of 0.41 ± 0.07 year−¹ and longevity of 4.04 ± 0.07 years. Pneumatophores showed average heights of 17.8 ± 0.8 cm with a density of 292 ± 30 pneumatophores m−² and average biomass of 453 ± 51 gDw m−². In conclusion, the production and biomass of subterranean roots and pneumatophores show spatial variations controlled by environmental factors as hydroperiod, interstitial redox potential, mangrove tree density and soil moisture content.


8.
- Artículo con arbitraje
*Solicítelo con su bibliotecario/a
Relationship among physicochemical conditions, chlorophyll-a concentration, and water level in a tropical river–floodplain system
Cruz Ramírez, Allan K. (autor) ; Salcedo Meza, Miguel Ángel (autor) ; Sánchez, A. J. (coaut.) ; Barba Macías, Everardo (autor) ; Mendoza Palacios, Juan de Dios (autor) ;
Contenido en: International Journal of Environmental Science and Technology Vol. 16, no. 7 (July 2019), p. 3869-3876 ISSN: 1735-2630
Nota: Solicítelo con su bibliotecario/a
PDF
Resumen en: Inglés |
Resumen en inglés

The free-flowing Usumacinta River maintains an average annual water-level fluctuation of 6.7 m. This study evaluated relationships between 14 physicochemical and biological variables and key factors in four water-level conditions in a river–floodplain system. The analysis incorporated intra-annual variation in all variables, with each selected in accordance with multiple statistical and physicochemical criteria. Possible correlations were examined as a function of various physicochemical and biological factors at each water level. Within the study area, defined by a temporal gradient in principal component 1, the yearly river overflow above the bankfull stage is characterized by water with a low level of total suspended solids. Data on riverine wetlands suggest that seasonal changes are key to determining intra- and inter-annual chlorophyll-a levels and water clarity. However, opposite trends are observed for high and low water-level conditions. Nutrient enrichment cannot be taken as the key physicochemical factor of water level, under either water-level conditions, due to the lack of a temporal gradient in principal component 2 and the high biochemical variability of nitrate and orthophosphate levels. In conclusion, the hypothesis was accepted for the production of phytoplankton biomass and light attenuation at low and high water levels, as both were dependent on intra-annual changes. The increases in chlorophyll-a related to the minimal variability at the lowest water level open the opportunity to gauge this relationship as a possible environmental predictor for river–floodplain systems.


9.
Capítulo de libro - Memoria en libro con arbitraje
Análisis espacio-temporal de la macrofauna edáfica en Calakmul, Campeche
Sánchez Silva, Sarai (autora) ; De Jong, Bernardus Hendricus Jozeph (autor) ; Huerta Lwanga, Esperanza (autora) ; Mendoza Vega, Jorge (autor) ; Aryal, Deb Raj (autor) ;
Disponible en línea
Contenido en: Estado actual del conocimiento del ciclo del carbono y sus interacciones en México: síntesis a 2018 Álamos, Sonora, México: Programa Mexicano del Carbono : Instituto Tecnológico de Sonora, 2018 páginas 484-491 ISBN:978-607-96490-6-7
PDF
Resumen en: Español | Inglés |
Resumen en español

Se analizaron la riqueza y abundancia de la macrofauna del suelo en época de lluvias y secas, en cuatro etapas sucesionales en Calakmul, Camp. México. En la temporada de lluvias se colectaron 3 352 individuos clasificados en 162 morfoespecies; en la temporada de secas se incrementó el número de individuos con 39 54 en 128 morfoespecies. Durante la temporada de lluvias todos los ordenes presentaron mayor abundancia. Los ordenes que presentaron diferencias significativas respecto a la temporada de secas fueron: diplura, isopoda, oligochaeta, pulmonta y thyssanura. No existen diferencias significativas en los parámetros poblacionales entre las etapas sucesionales. Características físico-químicas del sitio como el contenido de limo, N y la relación de C:N varían entre etapas sucesionales, lo que modifica la humedad del suelo y los nutrientes. Se realizó un PCA con las características físico-químicas del suelo, donde se obtuvo que la textura del suelo determina las unidades de paisaje. Con base en esta clasificación se aplicó el IndVal con el cual se identificó a los organismos Depredadores-detritívoros-fitófagos y detritívoros como los mejores indicadores para suelos arcillosos.

Resumen en inglés

The richness and abundance of the macrofauna of the soil during the rainy and dry season was pointed out in four successional stages in Calakmul, Camp. Mexico. During the rainy season, 3 352 individuals were classified in 162 morphospecies; in the dry season the number of individuals increased with 3 954 in 128 morphospecies. During the rainy season all orders increased. The orders with significant differences were: diplura, isopoda, oligochaeta, pulmonta and thyssanura. There were no significant differences in the population parameters between the successional stages. Physico-chemical characteristics of the site such as the silt and N content, and the C:N ratio differ between successional stages, these parameters modifies soil moisture and nutrients. A PCA analysis was carried out with the physical-chemical characteristics of the soil. The soil texture determines the landscape units. Based on this classification, the IndVal was applied, showing that Predator-detritivore-phytophagous and detritivore organisms were the best indicators for clay soils.


10.
- Artículo con arbitraje
Degradación de hojarasca y aporte de nutrientes del manglar en la Laguna Mecoacán, Golfo de México
Torres Velázquez, Jony Ramiro ; Infante Mata, Dulce María (coaut.) ; Sánchez Martínez, Alberto de Jesús (coaut.) ; Espinoza Tenorio, Alejandro (coaut.) ; Barba Macías, Everardo (coaut.) ;
Contenido en: Revista de Biología Tropical Vol. 66, no. 2 (June 2018), p. 892-907 ISSN: 0034-7744
PDF PDF
Resumen en: Español | Inglés |
Resumen en español

Los manglares son ecosistemas de importante productividad primaria, donde se establece un flujo de energía (nutrientes) con zonas adyacentes y su ambiente acuático, impulsado principalmente por los procesos de degradación. El objetivo del estudio fue estimar el coeficiente de degradación diario (k) de hoja de mangle por medio de bolsas de degradación, en relación con los factores físico químicos del suelo y el aporte de nutrientes (fósforo y nitrógeno) en sedimento del manglar de la Laguna Mecoacán, Golfo de México. El coeficiente de degradación se estimó por medio de bolsas de degradación de hojarasca en seis sitios de monitoreo mensual. Se identificó una rápida degradación durante el primer mes de hasta 51 % en Avicennia germinans (L.) Stearn asociado a procesos de lixiviación por condiciones de inundación. La degradación (k) de Rhizophora mangle L. (k= 0.0052 ± 0.0002) (F= 12.2 p<0.05 n= 216) y Laguncularia racemosa (L.) Gaertn (k= 0.005 ± 0.0003) (F= 3.7 p= 0.02 n= 108) difieren significativamente de A. germinans (k= 0.009 ± 0.0003) (F= 1.2 p= 0.02 n= 216). En relación al T50 de R. mangle y L. racemosa presentaron mayor tiempo de degradación (133 y 138 días respectivamente) comparado con A. germinans (74 días). Se registró una correlación significativa entre la materia orgánica y la humedad del suelo con la constante de descomposición de A. germinans (r= 0.65 p< 0.05 y r= 0.55 p< 0.05 respectivamente). El más alto contenido de nitrógeno total se dio en Pajaral (2 683 mg.Kg) y presentó alta correlación con el contenido de materia orgánica (r= 0.9 p= 0.03); en relación al fósforo total, el nivel más alto se presentó en Boca (2 031 mg.Kg) correlacionado de forma negativa con el pH (r= -0.61 p< 0.05).

En conclusión, las diferencias en la velocidad de degradación de las hojas de mangle dependen de la especie (composición foliar), tiempo de exposición o inmersión en agua (patrón de inundación) y heterogeneidad del sedimento (i.e., textura, pH, contenido de humedad y densidad aparente)

Resumen en inglés

Mangroves are ecosystems with a high primary productivity that is mainly driven mainly by degradation processes. Energy (nutrients) flows from mangroves toward adjacent zones and the surrounding aquatic environment. The objective of the present study was to estimate the daily degradation coefficient (k) of mangrove leaves in relation to physical-chemical soil factors and in situ nutrient supply (phosphorus and nitrogen) in Mecoacán Lagoon, Gulf of Mexico. Leaf litter degradation bags were placed at six monthly monitoring sites to evaluate degradation and to calculate the corresponding degradation coefficients. A rapid degradation of up to 51 % was observed for Avicennia germinans (L.) Stearn during the first month in association with leaching resulting from flood conditions. The degradation of Rhizophora mangle (L.) (k= 0.0052±0.0002) (F= 12.2 p< 0.05 n= 216) and Laguncularia racemosa (L.) Gaertn (k= 0.005±0.0003) (F= 3.7 p= 0.2 n= 108), differed significantly from that of A. germinans (k= 0.009 ± 0.0003) (F= 1.2 p= 0.2 n= 216) did not present significant differences. To reach T50 degradation, R. mangle and L. racemosa required more time (133 and 138 days, respectively) than A. germinans (74 days). Organic matter and soil humidity were significantly correlated with the decay constant of A. germinans (r= 0.65 p< 0.05 and r= 0.55 p< 0.05, respectively). Total nitrogen content was highest in the Pajaral site (2 683 mg.kg) and was also highly correlated with organic matter content (r= 0.9 p= 0.003). Total phosphorus content was highest in the Boca site (2 031 mg.kg) and was also negatively correlated with pH (r= -0.61 p= 0.004). In conclusion, differences in the rate of mangrove leaf degradation depend on the involved species (leaf composition), time of exposure or immersion in water (flooding patterns) and sediment heterogeneity (i.e., texture, pH, humidity content and bulk density).