Estructura poblacional del árbol Avicennia germinans (Acanthaceae) en un manglar alterado del Golfo de México / Population structure of Avicennia germinans trees (Acanthaceae) in a disturbed mangrove in the Gulf of Mexico

Resumen Introducción: Los manglares están en declive en el mundo, conocer su estructura y regeneración en diferentes niveles de alteración puede ayudar a comprender la dinámica poblacional ante situaciones de estrés. Objetivo: La meta principal del estudio fue analizar la estructura comunitaria y estimar la trayectoria de las poblaciones de Avicenia germinans en diferentes sitios de manglar que presentan tres niveles de alteración. Métodos: Ocho transectos de aproximadamente 500 m de largo y colocados de manera perpendicular a la laguna de Tampamachoco, Veracruz, interceptaron tres niveles de alteración en los sitios estudiados del bosque de manglar. En cada transecto, cuadrantes de 10 x 10 m, 5 x 5 m, y 1 x 1 m sirvieron para contar todos los árboles de mangle por especie y estadio de madurez en 2017 y 2018. Resultados: La especie más abundante fue: A. germinans seguida de Rhizophora mangle y Laguncularia racemosa. Con base en su abundancia, se encontraron diferencias significativas según los tres grados de alteración (AM R = 0.6, P < 0.001), ilustrado en un análisis de ordenación no métrico (nMDS). Una tabla de vida para A. germinans permitió un análisis poblacional que mostró una tasa intrínseca de incremento poblacional (r) negativa para los sitios que presentan alteración (-0.0027 u -0.0774) y positiva (0.0289) en el sitio sin alteración aparente. La supervivencia del estadio de plántula a juvenil varia de 50 % en el sitio no alterados a 5 y 4 % en los otros dos sitios. Conclusiones: Se necesitan medidas para incrementar la sobrevivencia de las plántulas y revertir la disminución de las trayectorias en los sitios con alteración, de otra forma el manglar tendrá una viabilidad reducida en el término medio.

Abstract Introduction: Globally, mangroves are declining; characterizing their structure and regeneration at different disturbance levels can help understand their responses to stressful situations. Objective: The study's primary goal was to analyze the mangrove community structure and to estimate the populations' trajectories of Avicenia germinans at different mangrove sites that present three levels of disturbance. Methods: Eight transects of approximately 500 m in length and laid perpendicular to the Tamapamchoco lagoon, Veracruz, intersected three levels of disturbance currently present on the mangrove forest. On each transect, 10 x 10 m, 5 x 5 m, and 1 x 1 m quadrants served to account for all mangrove trees by species and stage of maturity in 2017 and 2018. Results: The most abundant species was: A. germinans followed by Rhizophora mangle and Laguncularia racemosa. Based on their abundance, we found significant differences for the three levels of disturbance (ANOSIM R = 0.6, P < 0.001) presented in a non-metric ordination (nMDS). A life table for A. germinans allowed a population analysis that showed an intrinsic rate of population increase (r) that was negative at the disturbed sites (-0.0027 and -0.0774) and positive (0.0289) at the apparently undisturbed site. Seedling to juvenile stage survival ranged from 50 % at the undisturbed site to 5 and 4 % at the disturbed sites. Conclusions: Measures to increase the survival of seedlings are necessary to reverse the decreasing population trajectories at the disturbed sites; otherwise, the mangrove will have reduced viability in the medium term.

Petroleum contamination and bioaugmentation in bacterial rhizosphere communities from Avicennia schaueriana

ABSTRACT Anthropogenic activity, such as accidental oil spills, are typical sources of urban mangrove pollution that may affect mangrove bacterial communities as well as their mobile genetic elements. To evaluate remediation strategies, we followed over the time the effects of a petroleum hydrocarbon degrading consortium inoculated on mangrove tree Avicennia schaueriana against artificial petroleum contamination in a phytoremediation greenhouse experiment. Interestingly, despite plant protection due to the inoculation, denaturing gradient gel electrophoresis of the bacterial 16S rRNA gene fragments amplified from the total community DNA indicated that the different treatments did not significantly affect the bacterial community composition. However, while the bacterial community was rather stable, pronounced shifts were observed in the abundance of bacteria carrying plasmids. A PCR-Southern blot hybridization analysis indicated an increase in the abundance of IncP-9 catabolic plasmids. Denaturing gradient gel electrophoresis of naphthalene dioxygenase (ndo) genes amplified from cDNA (RNA) indicated the dominance of a specific ndo gene in the inoculated petroleum amendment treatment. The petroleum hydrocarbon degrading consortium characterization indicated the prevalence of bacteria assigned to Pseudomonas spp., Comamonas spp. and Ochrobactrum spp. IncP-9 plasmids were detected for the first time in Comamonas sp. and Ochrobactrum spp., which is a novelty of this study.

Diversity and distribution of epiphytic bromeliads in a Brazilian subtropical mangrove

ABSTRACT It is not unusual to find epiphytic bromeliads in mangroves, but most studies on mangrove vegetation do not record their presence. This study aimed to evaluate the diversity and distribution of epiphytic bromeliads in a subtropical mangrove. The richness, abundance and life form (atmospheric and tank) of bromeliads were recorded and compared among host tree species and waterline proximity. The effects of diameter and height of host trees on the abundance of bromeliads were also assessed. The mangrove was composed of Avicennia schaueriana, Laguncularia racemosa and Rhizophora mangle. We recorded seven bromeliad species of the genera Tillandsia and Vriesea. The waterline proximity did not affect the abundance or diversity of bromeliads, but atmospheric forms were predominant near the waterline, whereas tank bromeliads were more frequent in the interior of the mangrove. The three mangrove species hosted bromeliads, but L. racemosa was the preferred host. The species composition showed that the distribution of bromeliads is more related to the host species than to the distance from the waterline. Bromeliad abundance increased with tree size. Bromeliads can be biological indicators of ecosystem health; therefore, inventories and host tree preferences are necessary knowledge for an adequate management of sensitive ecosystems as mangroves.

Leaf morphological strategies of seedlings and saplings of Rhizophora mangle (Rhizophoraceae), Laguncularia racemosa (Combretaceae) and Avicennia schaueriana (Acanthaceae) from Southern Brazil

AbstractThe initial phase of a plant life cycle is a short and critical period, when individuals are more vulnerable to environmental factors. The morphological and anatomical study of seedlings and saplings leaf type enables the understanding of species strategies of fundamental importance in their establishment and survival. The objective of this study was to analyze the structure of seedlings and saplings leaf types of three mangrove species, Avicennia schaueriana, Laguncularia racemosa, Rhizophora mangle, to understand their early life adaptive strategies to the environment. A total of 30 fully expanded cotyledons (A. schaueriana and L. racemosa), 30 leaves of seedlings, and 30 leaves of saplings of each species were collected from a mangrove area in Guaratuba Bay, Paraná State, Brazil. Following standard methods, samples were prepared for morphological (leaf dry mass, density, thickness) and anatomical analysis (epidermis and sub-epidermal layers, stomata types, density of salt secretion glands, palisade and spongy parenchyma thickness). To compare leaf types among species one-way ANOVA and Principal Component Analysis were used, while Cluster Analysis evaluated differences between the species. We observed significant structural differences among species leaf types. A. schaueriana showed the thickest cotyledons, while L. racemosa presented a dorsiventral structure. Higher values of the specific leaf area were observed for seedlings leaves of A. schaueriana, cotyledons of L. racemosa and saplings leaves of A. schaueriana and R. mangle. Leaf density was similar to cotyledons and seedlings leaves in A. schaueriana and L. racemosa, while R. mangle had seedlings leaves denser than saplings. A. schaueriana and R. mangle showed hypostomatic leaves, while L. racemosa amphistomatic; besides, A. chaueriana showed diacytic stomata, while L. racemosa anomocytic, and R. mangle ciclocytic. Seedling leaves were thicker in R. mangle (535 µm) and L.racemosa (520 µm) than in A. schaueriana (470.3 µm); while saplings leaves were thicker in L. racemosa (568.3 µm) than in A. schaueriana seedlings (512.4 µm) and R. mangle (514.6 µm). Besides, seedlings leaves palisade parenchyma showed increasing thickness in L. racemosa (119.2 µm) <A. schaueriana (155.5 µm) <R. mangle (175.4 µm); while in saplings leaves as follows R. mangle (128.4 µm) <A. schaueriana (183.4 µm) <L. racemosa (193.9 µm). Similarly, seedlings leaves spongy parenchyma thickness values were as follows A. schaueriana (182.6 µm) = R. mangle (192.8 µm) <L. racemosa (354.4 µm); while in saplings were A. schaueriana (182.6 µm) = R. mangle (187.3 µm) <L. racemosa (331.3 µm). The analyzed traits, in different combinations, represent morphological adjustments of leaf types to reduce water loss, eliminate salt excess, increase the absorption of light, allowing a higher efficiency on the maintenance of physiological processes in this initial growth stage. Rev. Biol. Trop. 64 (1): 305-317. Epub 2016 March 01.

ResumenLa fase inicial del ciclo de vida de una planta es un período corto y crítico, cuando los individuos son más vulnerables a factores ambientales. El estudio morfológico y anatómico del tipo de hojas de las plántulas y árboles pequeños, permite la comprensión de las estrategias de las especies, que es de importancia fundamental para su establecimiento y supervivencia. El objetivo de este estudio fue analizar la estructura de los tipos de hojas de las plántulas y árboles pequeños de tres especies de mangle: Avicennia schaueriana, Laguncularia racemosa y Rhizophora mangle, para entender sus estrategias de vida tempranas de adaptación al ambiente. Un total de 30 cotiledones completamente abiertos (A. schaueriana y L. racemosa), 30 hojas de plántulas, y 30 hojas de árboles pequeños de cada especie se recolectaron en una área de manglar en Bahía Guaratuba, Estado de Paraná, Brasil. Siguiendo los métodos estándares, se prepararon muestras para análisis morfológicos (biomasa de hoja seca, densidad y espesor) y anatómicos (epidermis y capas sub-epidérmicas, tipos de estomas, densidad de glándulas secretoras de sal y grosor del parénquima empalizado y del esponjoso). Para comparar los tipos de hojas entre las especies se utilizaron un modelo lineal y Análisis de Componentes Principales, mientras que un análisis de conglomerados evaluó las diferencias entre las especies. Observamos diferencias estructurales significativas entre tipos de hoja en las especies. A.schaueriana mostró cotiledones más gruesos, mientras que L. racemosa presenta una estructura dorsiventral. Se observaron valores más altos del área foliar específica para las hojas de las plántulas de A. schaueriana, cotiledones de L. racemosa y hojas de árboles pequeños de A. schaueriana y R. mangle. La densidad de la hoja fue similar a la de los cotiledones y hojas de plántulas de A. schaueriana y L. racemosa, mientras que R. mangle tenía las hojas de las plántulas más gruesas que los árboles pequeños. A. schaueriana y R. mangle mostraron hojas hipostomáticas; L. racemosa anfiestomáticas; por otro lado A. chaueriana mostró estomas diacíticos, L. racemosa anomocíticos y R. mangle ciclocíticos. Las hojas de las plántulas eran más gruesas en R. mangle (535 micras) y L. racemosa (520 micras) que en A. schaueriana (470.3 m); mientras que las hojas de las plántulas eran más gruesas en L. racemosa (568.3 m) que en A. schaueriana (512.4 micras) y R. mangle (514.6 m). Además el parénquima empalizado de las plántulas mostró un aumento de espesor en L. racemosa (119.2 m) <A. schaueriana (155.5 m) <R. mangle (175.4 m); mientras que en las hojas de los árboles pequeños fue de siguiente manera: R. mangle (128.4 m) <A. schaueriana (183.4 m) <L. racemosa (193.9 m). Del mismo modo, en las hojas de las plántulas los valores del espesor del parénquima esponjoso fueron: A. schaueriana (182.6 m) = R. mangle (192.8 m) <L. racemosa (354.4 m); mientras que en los árboles pequeños: A. schaueriana (182.6 m) = R. mangle (187.3 m) <L. racemosa (331.3 m). Los rasgos analizados, en diferentes combinaciones, representan ajustes morfológicos de tipos de hojas para reducir la pérdida de agua, eliminar el exceso de sal, aumentar la absorción de la luz, lo que permite una mayor eficiencia en el mantenimiento de los procesos fisiológicos en esta etapa de crecimiento inicial.

Anatomical Changes during Rooting of Mangroves - Avicennia officinalis and Excoecaria agallocha.

Mangrove forests continue to disappear all over the world due to a number of reasons. This is the study made to screen the anatomical and biochemical changes during the rooting process. Two important mangrove species have been examined based on their salt relationship natures: Avicennia officinalis subsp. australasica (salt excreting plant) and Excoecaria agallocha L (salt accumulating plant). The plants were treated with different root promoting hormones like IBA, IAA and NAA at different concentrations for three minutes each. After 45 days of the growth period root growth and anatomical changes were observed. The roots originated from the deeper zone of the secondary xylem after several anatomical variations in the hormone treated plants. This is the first trial which may help to determine the mass propagation of these commercial and medicinally important mangroves.

Antimicrobial compounds from mangrove plants: A pharmaceutical prospective / 中国结合医学杂志

Mangroves are salt-tolerant forest ecosystem that extends between tropical and subtropical intertidal regions of the world. Mangroves are biochemically unique vegetation that produce wide array of natural products with immense medicinal potential. These plants are the most valuable resources and provide economic and ecological benefits to the coastal people. Natural products from these plants are of great interest as they provide innumerable direct and indirect benefits to human beings for the discovery of novel antimicrobial and other bioactive compounds. They possess active metabolites with some novel chemical structures that belong to diverse chemical classes such as alkaloids, phenol, steroids, terpenoids and tannins. Several mangrove species have been used in traditional medicine or have few applications as insecticide and pesticide. To date, several mangroves, and their associated species and solvent extracts are screened for antimicrobial activity along with the presence of potent bioactive compounds. The present article emphasizes and creates awareness about the potential mangrove plants and their associates as a source of biologically active compounds with potent antimicrobial properties. This paper also elaborates the mechanisms of action and various methods for screening of antimicrobial compounds.

Diversity and seasonal fluctuation of predominant microbial communities in Bhitarkanika, a tropical mangrove ecosystem in India

Different groups of microorganisms are present in mangrove areas, and they perform complex interactions for nutrient and ecological balances. Since little is known about microbial populations in mangroves, this study analyzed the microbial community structure and function in relation to soil physico-chemical properties in Bhitarkanika, a tropical mangrove ecosystem in India. Spatial and seasonal fluctuations of thirteen important groups of microorganisms were evaluated from the mangrove forest sediments during different seasons, along with soil physico-chemical parameters. The overall microbial load (x10(5)cfu/g soil) in soil declined in the order of heterotrophic, free living N2 fixing, Gram-negative nitrifying, sulphur oxidizing, Gram-positive, spore forming, denitrifying, anaerobic, phosphate solubilizing, cellulose degrading bacteria, fungi and actinomycetes. Populations of the heterotrophic, phosphate solubilizing, sulphur oxidizing bacteria and fungi were more represented in the rainy season, while, Gram-negative, Gram-positive, nitrifying, denitrifying, cellulose decomposing bacteria and actinomycetes in the winter season. The pool size of most of other microbes either declined or maintained throughout the season. Soil nutrients such as N, P, K (Kg/ha) and total C (%) contents were higher in the rainy season and they did not follow any common trend of changes throughout the study period. Soil pH and salinity (mS/cm) varied from 6-8 and 6.4-19.5, respectively, and they normally affected the microbial population dynamics. Determination of bacterial diversity in Bhitarkanika mangrove soil by culture method showed the predominance of bacterial genera such as Bacillus, Pseudomonas, Desulfotomaculum, Desulfovibrio, Desulfomonas, Methylococcus, Vibrio, Micrococcus, Klebsiella and Azotobacter. Principal component analysis (PCA) revealed a correlation among local environmental variables with the sampling locations on the microbial community in the mangrove soil. Rev. Biol. Trop. 60 (2): 909-924. Epub 2012 June 01.

En las zonas de manglares están presentes diferentes grupos de microorganismos, los cuales presentan complejas interacciones que afectan los balances ecológicos y de nutrientes. Debido a que se sabe poco sobre las poblaciones microbianas en los manglares, este estudio analiza la estructura y función de la comunidad microbiana según las propiedades físico-químicas del suelo en Bhitarkanika, un ecosistema de manglares tropicales en la India. Se evaluaron las fluctuaciones espaciales y temporales de 13 grupos de microorganismos importantes en el sedimento de los manglares durante diferentes temporadas y parámetros físico-químicos del suelo. La carga microbiana total (x10(5)cfu/g de suelo) en el suelo se redujo en la categoría de las heterotróficas, de las bacterias libres fijadoras de N2, Gram-negativas nitrificantes, oxidativas de azufre, Gram-positivas, formadoras de esporas, desnitrificantes, anaeróbicas, las solubilizadoras de fosfato, bacterias degradadoras de celulosa, hongos y actinomicetos. Las poblaciones de heterótrofos, solubilizadoras de fosfato, oxidativas de azufre y los hongos estuvieron más representadas en la temporada lluviosa, mientras que, las Gram-negativas y Gram-positivas, nitrificantes, desnitrificantes, descomponedoras de celulosa y los actinomicetos, en la temporada de invierno. El tamaño poblacional de otros microorganismos disminuyó o se mantuvo durante toda la temporada. Los nutrientes del suelo, tales como N, P, K (Kg/ha) y el contenido total de C (%) fueron mayores en la temporada de lluvias, y no siguieron ninguna tendencia común de cambio a través del período de estudio. El pH del suelo y la salinidad (mS/cm) variaron de 6-8 y 6.4-19.5, respectivamente, lo que afectó significativamente la dinámica de la población microbiana. La determinación de la diversidad de bacterias en el suelo del manglar Bhitarkanika por el método de cultivo mostró el predominio de los géneros de bacterias como Bacillus, Pseudomonas, Desulfotomaculum, Desulfovibrio, Desulfomonas, Methylococcus, Vibrio, Micrococcus, Klebsiella y Azotobacter. El análisis de componentes principales (ACP) reveló una correlación entre las variables locales del ambiente y los sitios de muestreo en la comunidad microbiana en el suelo del manglar.

Interspecific variation of the bacterial community structure in the phyllosphere of the three major plant components of mangrove forests

Mangrove forests encompass a group of trees species that inhabit the intertidal zones, where soil is characterized by the high salinity and low availability of oxygen. The phyllosphere of these trees represent the habitat provided on the aboveground parts of plants, supporting in a global scale, a large and complex microbial community. The structure of phyllosphere communities reflects immigration, survival and growth of microbial colonizers, which is influenced by numerous environmental factors in addition to leaf physical and chemical properties. Here, a combination of culture-base methods with PCR-DGGE was applied to test whether local or plant specific factors shape the bacterial community of the phyllosphere from three plant species (Avicenia shaueriana, Laguncularia racemosa and Rhizophora mangle), found in two mangroves. The number of bacteria in the phyllosphere of these plants varied between 3.62 x 10(4) in A. schaeriana and 6.26 x 10³ in R. mangle. The results obtained by PCR-DGGE and isolation approaches were congruent and demonstrated that each plant species harbor specific bacterial communities in their leaves surfaces. Moreover, the ordination of environmental factors (mangrove and plant species), by redundancy analysis (RDA), also indicated that the selection exerted by plant species is higher than mangrove location on bacterial communities at phyllosphere.

Anticancer and antimicrobial activity of mangrove derived fungi Hypocrea lixii VB1 / 中国天然药物

AIM@#Mangrove is one of the oldest living tree species and its leaves are among the most extensively studied botanicals in use today. Scientific research throughout the world has found evidence to support the fact that its foliar extracts have great potential against human microbial pathogens. This study highlights the isolation of foliar fungi from Rhizophora mucronata, Avicenna officialis and Avicenna marina.@*METHOD@#It was isolated in Sabouroud's Dextrose Agar and mass cultivation was done in Sabouroud's Dextrose broth.@*RESULTS@#The ethyl acetate extract showed maximum antibacterial activity which inturn checked for different concentration against bacterial pathogens and anticancer activity for Hep2 and MCF7 cell line in vitro. The DNA was isolated from the fungi and the ITS region of 5.8 s RNA was sequenced and assigned to new species as they are separated from the type strains phylogenetic neighbors by sequence similarities.@*CONCLUSION@#This preliminary screening of fungal endophytes revealed their potential to yield potent bioactive compounds for drug discovery programmes.

Fatty acids in an estuarine mangrove ecosystem

Fatty acids have been successfully used to trace the transfer of organic matter in coastal and estuarine food webs. To delineate these web connections, fatty acid profiles were analyzed in species of microbes (Azotobacter vinelandii, and Lactobacillus xylosus), prawns (Metapenaeus monoceros and Macrobrachium rosenbergii) and finfish (Mugil cephalus), that are associated with decomposing leaves of two mangrove species, Rhizophora apiculata and Avicennia marina. The fatty acids, except long chain fatty acids, exhibit changes during decomposition of mangrove leaves with a reduction of saturated fatty acids and an increase of monounsaturated fatty acids. The branched fatty acids are absent in undecomposed mangrove leaves, but present significantly in the decomposed leaves and in prawns and finfish, representing an important source for them. This revealed that the microbes are dominant producers that contribute significantly to the fishes and prawns in the mangrove ecosystem. This work has proved the fatty acid biomarkers as an effective tool for identifying the trophic interactions among dominant producers and consumers in this mangrove. Rev. Biol. Trop. 58 (2): 577-587. Epub 2010 June 02.

Los ácidos grasos se han utilizado con éxito para estudiar la transferencia de materia orgánica en las redes alimentarias costeras y estuarinas. Para delinear las interacciones tróficas en las redes, se analizaron perfiles de ácidos grasos en las especies de microbios (Azotobacter vinelandii y Lactobacillus xylosus), camarones (Metapenaeus monoceros y Macrobrachium rosenbergii) y peces (Mugil cephalus), que están asociadas con la descomposición de las hojas de dos especies de mangle, Rhizophora apiculata y Avicennia marina. Los ácidos grasos, con excepción de los de cadena larga, exhiben cambios durante la descomposición de las hojas de mangle, con una reducción de los ácidos grasos saturados y un aumento de los monoinsaturados. Los ácidos grasos ramificados están ausentes en las hojas de mangle sin descomponer, pero presentes de manera significativa en las hojas descompuestas, en camarones y peces, representando una fuente importante para ellos. Esto revela que los microbios son productores dominantes que contribuyen significativamente con los peces y camarones en el ecosistema de manglar. Este trabajo demuestra que los marcadores biológicos de los ácidos grasos son una herramienta eficaz para la identificación de las interacciones tróficas entre los productores dominantes y consumidores en este manglar.

Los manglares de Costa Rica: el Pacífico norte

Abstract: Costa Rica mangroves: the north Pacific. Costa Rica has mangrove forests on both the Caribbean and Pacific coasts. The Pacific side has 99% of the mangrove area of the country. In this review we compile available information on the mangroves of the north Pacific coast of Costa Rica, from Bahía Salinas, on the border with Nicaragua, to the tip of the Peninsula de Nicoya at Cabo Blanco. We provide information on the location of the mangroves and all available information for each mangrove forest. These mangrove communities are smaller in extension and tree sizes, and have lower diversity compared to the mangroves on the southern section of the Pacific coast of Costa Rica. The dominant species are Rhizophora mangle and Rhizophora racemosa along the canal edges, backed by Avicennia germinans, and farther inland Avicennia bicolor, Laguncularia racemosa and Conocarpus erectus. At Potrero Grande a healthy population of Pelliciera rhizophorae, a rare species, has been reported. We recognized 38 mangrove communities in this part of the country, based on the National Wetland Inventory, published papers, field observations, theses, technical reports, and the national topographic maps (1:50 000, Instituto Geográfico Nacional). Relatively detailed information could be found for only five mangrove forests, for 14 more only prelimary and incomplete lists of plants and in some cases of animal species are available, for nine there is even less information, and for nine more only their location is known, which in some cases was not correct. Detail mapping, characterization of the vegetation and fauna, physiological studies, analyses of biogeochemical and physical processes, economic valuations, and determination of the health status of the mangrove of the northern Pacific coast, as well as for the rest of Costa Rica, are neccesary and urgent. Rev. Biol. Trop. 57 (3): 473-488. Epub 2009 September 30.

Costa Rica tiene bosques de manglar en las costas Caribe y Pacífica. El 99% de los manglares del país se encuentran en la costa Pacífica. En este trabajo recopilamos la información disponible sobre los manglares del Pacífico norte de Costa Rica, desde la frontera con Nicaragua hasta la Reserva Absoluta de Cabo Blanco, en la punta sur de la Península de Nicoya. La ubicación de los manglares y cualquier información disponible para cada manglar es resumida. El clima de esta región es seco con estaciones de lluvia y sequía muy bien definidas. Los manglares del norte son relativamente pequeños en extensión y tamaño de árboles, y de baja diversidad comparados con los del Pacífico sur de Costa Rica. Las principales especies de mangle son: Rhizophora mangle, Rhizophora racemosa a lo largo de los bordes de los canales, seguido por Avicennia germinans, y más tierra adentro Avicennia bicolor, Laguncularia racemosa y Conocarpus erectus. En el manglar de Potrero Grande se informa de una población saludable de la especie de Pelliciera rhizophorae, especies muy poco abundante. Reconocemos 38 comunidades de manglares en el Pacífico norte de Costa Rica basado en el Inventario Nacional de Humedales, artículos publicados, observaciones de campo, tesis, informes técnicos y los mapas 1: 50 000 del Instituto Geográfico Nacional. Se pudo encontrar información relativamente detallada pero fragmentada de únicamente cinco manglares (los descritos en esta publicación), de 14 solamente hay listas preliminares e incompletas de plantas y en algunos casos de animales, de nueve manglares más hay información todavía más limitada, y de otros nueve se conoce solamente su ubicación, que en algunos casos se comprobó que era incorrecta. Trabajos de mapeo detallado, caracterización de la vegetación y la fauna, estudios fisiológicos, análisis de procesos biogeoquímicos, evaluaciones económicas, y determinación del estado de salud de los manglares del Pacífico norte de Costa Rica, y del resto del país son necesarios y urgentes.

Seasonal variations in physico-chemical characteristics of Pichavaram mangroves, southeast coast of India.

All the physico-chemical parameters such as temperature, salinity pH, dissolved oxygen and nutrients like nitrate, nitrite, inorganic phosphate and reactive silicate were studied in Pichavaram mangroves, southeast coast of India, for a period of two years (April 2000-March 2002). Air and surface water temperatures varied from 27 degrees C to 38 degrees C and from 26 degrees C to 37 degrees C. Salinity varied from 3.0 per thousand to 33.0 per thousand and the pH ranged between 7.2 and 8.2. Variation in dissolved oxygen content was from 2.4 to 5.0 ml l(-1). Concentrations of nutrients viz nitrates (9.50 to 32.12 microM), nitrites (1.07 to 5.99 microM), phosphates (0.73 to 2.36 microM) and reactive silicates (22.1 to 89.8 microM) also varied independently.

Spectral reflectance properties of mangrove species of the Muthupettai mangrove environment, Tamil Nadu.

In the Muthupettai mangrove environment, spectral properties of six mangrove species viz. Avicennia marina, Aegiceras corniculatum, Excoecaria agallocha, Acanthus ilicifolius, Suaeda monoica and S. maritima was studied using Multi band Ground Truth Radiometer (Model-041). The study found that the chlorophyll concentration of different mangrove leaves varies between 0.05 and 0.36 mg g(-1), registering the minimum in S. maritima and maximum in E. agallocha. Interestingly species with higher chlorophyll concentration showed lower reflectance values alteast in the spectral bands 1 and 2. E. agallocha registered 0.36 mg g(-1) of chlorophyll while it recorded only 2.18 and 2.43% reflectance where as S. maritima recorded 3.16 and 3.27% of reflectance in bands 1 and 2. This indicates chlorophyll concentration is one of major factors responsible in determining the reflectance pattern of the pant communities. The spectral properties of mangroves were largely differed with that of the water and soil samples collected from the same locations, these results favourd the utilization of remotely sensed data for depicting various water and soil quality parameters from that of mangrove species in the mangrove environment. This study also found that the difference in reflectance of mangroves at canopy level is not only influenced by the chlorophyll content of species but also by the prevailing environmental condition and background reflectance of soil and water as well.

Spatial and temporal variations of meiofaunal communities from the western sector of the Gulf of Batabanó, Cuba: III. Vertical distribution

The vertical distribution of meiofauna within subtidal sediments was studied in four stations pertaining to mangrove or muddy flats habitats. In 2003, replicated samples were taken in dry (February) and wet (July) seasons at the Bacunagua Inlet, southwestern coast of Cuba. The abundance and number of meiofaunal taxa exhibited a vertical gradient possibly due to changes in the concentrations of oxygen and hydrogen sulphide, rather than food availability along this gradient. Nematodes are capable of distributing themselves throughout the whole sediment column due to their ability to tolerate reducing conditions; however depletion of communities along depth was evident. Their presence in deeper sediments (6 - 10 cm) suggests that certain species are adequately adapted to spend their entire life cycle in these harsh environments (where soluble tannins and decomposing organic matter predominate). Copepods showed a strong limitation to vertical distribution (concentrating in the top 2 cm), possibly in response to a sharp vertical decline in oxygenation within these organically enriched sediments. Rev. Biol. Trop. 56 (3): 1127-1134. Epub 2008 September 30.

Se estudió la distribución vertical de la meiofauna dentro de los sedimentos en cuatro estaciones ubicadas en manglares y planos fangosos. En el año 2003, tomamos muestras (con repetición) en época de seca (febrero) y de lluvia (julio) en la ensenada de Bacunagua, costa suroccidental de Cuba. La abundancia y el número de táxones de la meiofauna mostraron un gradiente vertical debido posiblemente a cambios en las concentraciones de oxígeno y sulfuro de hidrógeno, más que a la disponibilidad de alimento a lo largo del gradiente. Los nemátodos son capaces de distribuirse a través de la columna de sedimento debido a su habilidad para tolerar condiciones reducidas; sin embargo, fue evidente la reducción de las comunidades con la profundidad. Su presencia en los sedimentos profundos (6-10 cm) sugiere que ciertas especies están adecuadamente adaptadas a permanecer todo su ciclo de vida en un ambiente adverso (donde predominan los taninos solubles y la descomposición de la materia orgánica). Los copépodos mostraron una fuerte limitación en su distribución vertical (concentrándose en los 2 cm superficiales) posiblemente como respuesta a un gradiente marcado en la oxigenación dentro de estos sedimentos enriquecidos orgánicamente.

Application of sediment quality guidelines in the assessment of mangrove surface sediment in Mengkabong Lagoon, Sabah, Malaysia

There have been numerous sediment quality guidelines developed to monitor the sediments. Sediment quality guidelines are very useful to screen sediment contamination by comparing sediment contaminant concentration with the corresponding quality guideline, provide useful tools for screening sediment chemical data to identify pollutants of concern and prioritise problem sites and relatively good predictors of contaminations. However, these guidelines are chemical specific and do not include biological parameters. Aquatic ecosystems, including sediments, must be assessed in multiple components [biological data, toxicity, physicochemistry] by using integrated approaches in order to establish a complete and comprehensive set of sediment quality guidelines. Numerous sediment quality guidelines Washington Department of Ecology Sediment Quality Guideline, Australian and New Zealand Environment and Conservation Council, Swedish Environmental Sediment Quality, Screening Quick Reference Table, Portuguese Legislation on the Classification of Dredged Materials in Coastal Zones and Interim Sediment Quality Guideline for Hong Kong have been applied to the Mengkabong lagoon mangrove sediment and discussed. The most appropriate guideline that meets the prioritization criteria consistent with international initiatives and regulations is interim sediment quality values for Hong Kong. The guideline verifies that all the metals are below the Interim Sediment Quality Value-low. However, site-specific, biological testing and ecological analysis of exisiting benthics community structure related to sediment contamination are needed for final decision making in the case of Mengkabong lagoon

Spectral characterization of mangrove leaves in the Brazilian Amazonian Coast: Turiaçu Bay, Maranhão State

Mangrove communities are tropical systems which have fewer species than tropical forests, especially in Latin America and display a single architecture, usually lacking the various strata commonly found in other forest ecosystems. The identification of mangrove communities by orbital data is not a difficult task but the most interesting challenge is to identify themselves by the dominant species. The first step toward that floristic identification is the spectral characterization of detached leaves. Leaves from four species of mangrove trees were spectrally characterized considering the Directional Hemispherical Reflectance Factor (DHRF) determined through radiometric measurements using an integrating sphere LICOR 1800 attached to a spectroradiometer SPECTRON SE-590. In the visible bands (0.45-0.69 µm) the button-shaped mangrove Conocarpus erectus was brighter and the red mangrove Rhizophora mangle was darker than the other two species which shows very close DHRF values. Otherwise the black mangrove Avicennia germinans and the white mangrove Laguncularia racemosa can be distinguished from one another in the Near Infra Red (NIR) region (0.76-0.90 µm and in this region of the spectrum the DHRF of C. erectus and R. mangle become very close.

Comunidades de manguezais são sistemas tropicais que apresentam poucas espécies constituintes em relação às florestas tropicais úmidas, especialmente na América Latina e apresentam arquitetura simples, freqüentemente com a falta de vários estratos encontrados em outros ecossistemas florestais. A identificação de manguezais mediante a observação de dados orbitais não é uma tarefa muito complicada, porém um desafio interessante seria sua diferenciação mediante a identificação de espécies dominantes. O primeiro passo para essa identificação florística é a caracterização espectral de folhas isoladas. Folhas de quatro espécies arbóreas de manguezais foram caracterizadas espectralmente considerando o Fator de Reflectância Direcional-Hemisférico (FRDH) determinado através de medidas radiométricas realizadas com o uso de uma esfera integradora LICOR 1800, acoplada a um espectrorradiômetro SPECTRON SE-590. Na região do visível (0,45-0,69 mm), o denominado mangue de folhas arredondadas de Canocarpus erectus foi o mais brilhante e o mangue vermelho de Rhizophora mangle foi o mais escuro, em comparação com os dois demais manguezais estudados, que apresentaram valores de FRDH muito próximos entre si. O denominado mangue preto de Avicennia germinans pode ser distinguido do mangue branco de Laguncularia racemosa na região do Infravermelho Próximo (0,76-0,90 mm) e nessa mesma região, os espectros de FRDH de C. erectus e de R. mangle foram muito similares entre si.

Dial organic carbon fluctuations in a mangrove tidal creek in Sepetiba bay, Southeast Brazil

The carbon (C) concentration and flux, as dissolved organic carbon (DOC), particulate organic carbon (POC) and macrodetritus (MD), were quantified through 4 tidal cycles in a mangrove tidal creek in Southeastern Brazil. DOC was the major fraction of the total C concentration, accounting for 68 and 61 percent of the total C concentration during ebb and flood periods respectively. Concentrations of DOC (Ebb = 3,41 ± 0,57 mgC.L-1 and Flood = 3,55 ± 0,76 mgC.L-1) and POC (Ebb = 1,73 ± 0,99 mgC.L-1 and Flood = 1,28 ± 0,45 mgC.L-1) were relatively similar during the four tidal cycles. Macrodetritus presented a wide variation with concentration peaks probably related to external forces, such as winds, which enrich the ebb flow with leaf litter. DOC and POC fluxes depended primarily on tidal and net water fluxes, whereas MD fluxes were not. The magnitude of the DOC and POC fluxes varied with the area flooded at high tide, but not the MD fluxes. DOC was the major form of carbon export to Sepetiba Bay. During the four tidal cycles, the forest exported a total of 1,2 kg of organic carbon per ha, mostly as DOC (60 percent), followed by POC (22 percent) and MD (18 percent).

As concentrações e fluxos de carbono orgânico sob forma de carbono orgânico dissolvido (COD), carbono orgânico particulado (COP) e macrodetritos (MD) foram quantificadas durante 4 ciclos de maré em canal de maré na Floresta Experimental de Itacuruçá, Baía de Sepetiba, RJ, litoral sudeste do Brasil. COD foi a fração mais importante para a concentração total de carbono orgânico, contribuindo com 68 e 61 por cento da concentração total de C nos períodos de maré vazante e enchente, respectivamente. As concentrações de COD (vazante = 3.41 ± 0.57 mgC.L-1 e enchente = 3.55 ± 0.76 mgC.L-1) e COP (vazante = 1.73 ± 0.99 mgC.L-1 e enchente = 1.28 ± 0.45 mgC.L-1) foram similares durante os 4 ciclos de maré. A fração macrodetritos apresentou uma ampla variabilidade com máximos de concentração relacionados a fatores externos como ventos, que enriqueceram as águas de vazante com macrodetritos. A magnitude dos fluxos de COD e COP, mas não os de macrodetritos, relacionaram-se com os fluxos de água e a conseqüente área inundada pela maré. A fração COD foi a mais importante forma de exportação de carbono orgânico pelo manguezal. Durante os 4 ciclos monitorados, a floresta exportou um total de 1.2 kg de carbono orgânico, 60 por cento sob forma de COD, seguido pelo COP (22 por cento) e pela fração macrodetritos (18 por cento).

Growth of Avicennia marina and Ceriops decandra seedlings inoculated with halophilic azotobacters.

Inoculation of azotobacter has significant positive effects on the growth characteristics and pigments in mangrove seedlings of Avicennia marina and Ceriops decandra. The bacterial inoculation significantly increased the root dry biomass at the maximum of 75.8% at 30 gl(-1) salinity in Ceriops decandra. But in Avicennia marina, the shoot dry biomass was increased significantly at the maximum of 56.12% at 30 gl(-1) salinity in general, the Azotobacter beijerinkii improved the growth characteristics better in both species of mangroves preferably at higher salinity levels in A. marina and at a range of salinity in C. decandra. The results recommend this forraising vigorous seedlings under nursery conditions.

Microbial flora associated with submerged mangrove leaf litter in India

We studied the microbial flora in decomposing mangrove leaves in relation to changes in nitrogen and tannin levels, and in penaeid prawn assemblages. Senescent leaves of two mangrove species (Rhizophora apiculata and Avicennia marina) kept in nylon bags, were separately immersed for 80 days in five tanks full of mangrove water. A known amount of decomposing leaves was collected every ten days from each tank for microorganism counts, total nitrogen and tannin measurement, and juvenile penaeid prawn counts. Five genera of total heterotrophic bacteria (THB), three species of azotobacters and 19 species of fungi were identified. The azotobacters showed a significant peak around 40-50 days after the beginning of of decomposition, similar to the trend for total nitrogen and for prawn assemblages. Rev. Biol. Trop. 55 (2): 393-400. Epub 2007 June, 29.

Se estudió la flora microbiana en hojas en descomposición de mangles, considerando nitrógeno, taninos y camarones peneidos jóvenes. Colocamos hojas viejas de dos especies de mangle (Rhizophora apiculata y Avicennia marina) en bolsas de nylon y las sumergimos en agua de manglar durante 80 días usando cinco tanques separados. Cada diez días extrajimos una cantidad conocida de hojas en descomposición de cada tanque. Hallamos cinco géneros de bacterias heterotróficas totales (THB), tres especies de azotobacterias y 19 especies de hongos. Las azotobacterias presentaron un pico significativo de abundancia alrededor de los 40-50 días de descomposición, un patrón similar a los del nitrógeno total y los camarones.

Estructura y dinámica del manglar del delta del río Ranchería, Caribe colombiano / Structure and dynamics of the mangrove forest in the Rancheria River delta, Colombian Caribbean

We registered seedling survival and biomass increase for Rhizophora mangle L., Avicennia germinans L. and Laguncularia racemosa (L.) Gaertn. f, main mangrove species in the Rancheria River delta, Colombia. Only seedlings of R. mangle were found to survive. We also measured maximum rate of litterfall. We estimated annual litterfall through interpolation within an exponential regression performed with maximum and annual litterfall data published in other sources; the value of annual litterfall for the area was estimated to be 12.9 mgha(-1)y(-1). We found a 7.4 mgha(-1)y(-1)(-1) increase in biomass. Litterfall constitutes the larger fraction of the 20.2 mgha(-1)y(-1) productivity of this mangrove. We believe this is a very high value for a forest under unfavorable natural and human conditions, such as high seasonality and continuous use of the forest to feed goats and sheep. We consider that the high productivity is a response to both natural and anthropogenic stress.