Chlorococcales (algee: chlorophyceae) found in aquatic environments of the colombian amazon basin

Ten taxa of algae belonging to the order Chlorococcales are recorded for the first time from the Colombian Amazon basin. Two of these, Nephrocytium limneticum and Sorastrum americanum var. americanum, are recorded for the first time in Colombia.Se registran por primera vez para la Amazonia colombiana 10 taxones de Chlorococcales del fitoplancton y ticoplancton encontrados en algunos lagos del río Amazonas y del río Cotuhé, afluente del río Putumayo. Nephrocytium limneticum y Sorastrum americanum varo americanum son primeros registros para Colombia

Microalgas acuáticas de la Amazonía colombiana

Los estudios de microalgas se han adelantado en lagos y ríos ubicados en la frontera colombo - brasilera conocida como el eje Apaporis - Tabatinga (PAT), en ecosistemas de los ríos Amazonas y Putumayo, donde existe información ecológica (Duque 1997, Duque et al. 1997). Este trabajo es el primer acercamiento de información publicada sobre algunos grupos de microalgas acuáticas del eje PAT incluyendo la trofía y distribución geográfica de los taxa en ecosistemas acuáticos de Colombia (Duque 2000)

Chlorococcales of the Colombian Amazon. II

In this paper 41 taxa belonging to the families Coelastraceae, Chlorococcaceae, Radiococcaceae, Palmellaceae, Oocystaceae, Characiaceae, Treubariaceae, Botryococcaceae, Micractiniaceae and Hydrodictyaceae of the order Chlorococcales were recorded. The material studied was collected in rivers and lakes from Colombian Amazon basin. Among the total taxa recorded, 20 are new for Colombia and 10 are new for the Colombian region of the basin. The family best represented in terms of species richness was Oocystaceae, with 10 taxa, and the largest number of taxa was found in lakes Yahuarcaca (Amazon River).En el presente trabajo se registran 41 taxa, pertenecientes a las familias Coelastraceae, Chlorococcaceae, Radiococcaceae, Palmellaceae, Oocystaceae, Characiaceae, Treubariaceae, Botryococcaceae, Micractiniaceae e Hydrodictyaceae (orden Chlrorococcales) hallados en ríos y lagos de la cuenca de Amazonia Colombiana. Del total encontrado, 20 son nuevas citas para el país y 10 para la cuenca en Colombia. La familia mejor representada, en cuanto a riqueza específica, fue Oocystaceae con 10 taxa y en los lagos Yahuarcaca (Río Amazonas) se ha registrado el mayor número de taxa del orden.Facultad de Ciencias Naturales y Muse

PAPEL TRÓFICO DEL ZOOPLANCTON A TRAVÉS DEL ANÁLISIS DE ISÓTOPOS ESTABLES EN UN LAGO DE INUNDACIÓN EN LA AMAZONIA COLOMBIANA

Para caracterizar las fuentes primarias de carbono del zooplancton y su flujo en la red trófica en un lago de inundación próximo a la ciudad de Leticia (Amazonas, Colombia), se hicieron recolectas de bacterias, detritos, fitoplancton, perifiton y zooplancton entre mayo de 2010 y mayo de 2011. El zooplancton se usó como integrador por su posición central en la red trófica y para tal fin fueron analizados en términos de δ13C y δ15N los organismos concentrados en malla de 60μm, representados por cladócera, copépoda ciclopoida y rotífera. Las muestras fueron concentradas con filtros GF/F pre quemados para su análisis en el laboratorio de isotopos estables de la UNESP en Botucatú (SP). Los valores de δ13C muestran una relación trófica pobre entre el zooplancton (-37,99‰ ± 2,14) y sus fuentes potenciales como fitoplancton (-32,53‰ ± 1,97) perifiton (-32,56‰ ± 1,55) y detritos (-32,27‰ ± 0,81). Por otra parte, si bien los valores de δ15N del zooplancton (6,12‰ ± 0,59) complementan la apreciación sobre el fitoplancton (7,38‰ ± 1,1), sugieren el consumo de perifiton empobrecido (1,15‰ ± 0,07) y de detrito (5,23‰ ± 4,76). Los valores bajos de δ13C son asociados con el consumo de una fracción de carbono metanogénico, como ha sido demostrado en el hipolimnio de lagos de inundación, de la misma forma que su aporte a las capas superiores de la columna de agua durante eventos de mezcla. Esta especialización del zooplancton en consumir una fracción de varios gremios tróficos puede ser el resultado de la variabilidad intrínseca de los recursos, como resultado de las variaciones biogeoquímicas asociadas con la hidrología del lago

Componentes alimenticios de podocnemis unifilis y p. Expansa (testudines: podocnemididae) en el resguardo curare-los ingleses, amazonas, colombia

Studies of the diet of aquatic turtles are important to develop and to base management plans and habitat preservation. This study aims to allow the identification of the diet of Podocnemis unifilis and Podocnemis expansa. The methods were routes of identification in the varzea (flooding forest), near to the beach (low waters), ascending and descending waters near to lakes and tributaries of the Caquetá river (Colombian Amazon). Data were collected with semi structured interviews with indigenous communities of Curare-Los Ingleses and by analysis of items of stomach contents from hunted turtles. Fruits and seeds were the principal diet of both species. The more important families were Bignoniaceae, Euphorbiaceae, Mimosaceae, and Cecropiaceae in P. unifilis, and for P. expansa were Fabaceae, Moraceae, Euphorbiaceae and Cecropiaceae; all plant material was identified by Sede Amazonia and the Instituto de Ciencias Naturales de la Universidad Nacional de Colombia. Thirty four of the identified plant species mentioned by local people for P. expansa 64% was coincident with food items documented , likewise of the 26 identified plant species referred to by local people for P. unifilis 80% was localized in stomach contents.El estudio de los componentes alimenticios de los quelonios es importante para fundamentar planes de manejo y la preservación de sus hábitats. En este trabajo se reportan los ítems alimenticios de Podocnemis unifilis y P. expansa. Para tal fin fueron realizadas colectas durante las temporadas de aguas ascendentes, altas, descendentes y bajas, en los lagos y afluentes cercanos al río Caquetá, Amazonas, Colombia. Fueron colectados y analizados los contenidos estomacales de tortugas muertas por los comunitarios. Informaciones adicionales sobre los ítems alimenticios fueron obtenidas por medio de entrevistas semiestructuradas con miembros de las comunidades indígenas del resguardo Curare-Los Ingleses. Las muestras botánicas colectadas fueron identificadas en la Sede Amazonia y el Instituto de Ciencias Naturales de la Universidad Nacional de Colombia. El alimento predominante en la alimentación de ambas especies es material vegetal. En P. unifilis las familias botánicas más representativas fueron Bignoniaceae, Euphorbiaceae, Mimosaceae y Cecropiaceae y para P. expansa, Fabaceae, Moraceae, Euphorbiaceae y Cecropiaceae. De las 34 especies de plantas referidas por los comunitarios para P. expansa, se encontró que 64% coincidió con los ítems de los contenidos estomacales examinados, mientras que para P. unifilis de las 26 especies de plantas comentadas, 76,9% fue encontrado en los contenidos estomacales

Structural Changes of the Periphytic Community in the Yahuarcaca Lake System, Colombian Amazon

El estudio analiza el proceso de sucesión de la comunidad perifítica en las fracciones bacteriana, algal y de protozoos, durante los períodos limnológicos de aguas bajas y aguas altas en el sistema lagunar de Yahuarcaca, ubicado en la llanura aluvial del río Amazonas (Leticia, Colombia). Cada 12 h, durante tres días, fueron recolectadas tres láminas de acetato por ambiente (región limnética y entre los macrófitos). El proceso de colonización bacteriana para el período de aguas bajas inició a las 12 h con valores de 2,98 x 106 — 1,84 x 106 cel/ml; a las 36 y 48 h con 6,36 x 106 — 6,16 x 106 cel/ml y finalizó con un descenso de 2,57 x 106 — 1,32 x 106 cel/ml a las 72 h. Para el período de aguas altas se presentó un aumento en la densidad de este componente con valores iniciales de 1,55 x 107 — 8,54 x 106 cel/ml. En la primera etapa de colonización algal predominaron los géneros bidimensionales. En la segunda etapa Gomphonema aff., G. gracile, Melosira varians y Pinnularia sp.; y en la última fase se encontraron especies como Fragillaria aff. intermedia, F. aff. ulna, Aulacoseira varians, Oedogonium sp., Ulothix sp. y Nostoc sp. Entre los protozoos, los primeros colonizadores fueron los flagelados, seguidos de los ciliados bacteriófagos de vida libre que dieron paso a los ciliados fijos (tipo vorticélidos). La temperatura y la conductividad fueron las variables que presentaron mayor relación con la fracción algal, al contrario de la fracción bacteriana, que dominó al inicio del proceso. Para los protozoos, el pH fue el factor que más influyó en la presencia y abundancia durante la sucesión, presentando dominancia hacia las horas finales durante los dos períodos limnológicos. La disminución y aparición de nuevas especies de algas hacia las horas finales del proceso de colonización, evidenciaron un cambio en la estructura del perifiton y una sucesión de la comunidad en un lapso de 72 h para este sistema de la Amazonia colombiana.The study analyzes the succession process of the periphytic community in the bacterial, algal and protozoal fractions during the limnological periods of low water and high water in the lagoon system of Yahuarcaca, located in the floodplain of the Amazon River (Leticia, Colombia). Every 12 hours, for three days, three sheets of acetate per environment were collected (limnetic region and between macrophytes). The process of bacterial colonization for the low-water period began at the twelfth hour with values of 2.98 x 106 ― 1.84 x 106 cells/ml; at hours 36 and 48, with 6.36 x 106 — 6.16 x 106 cells/ml and ended with a decline of 2.57 x 106 — 1.32 x 106 cells/ml at hour 72. For the period of high water there was an increase in the density of this component, with initial values of 1.55 x 107 — 8.54 x 106 cells/ml. In the first stage of the algal colonization the two-dimensional genres predominated. In the second stage, Gomphonema aff., G. gracile, Melosira varians and Pinnularia sp.; and in the last phase, species such as Fragillaria aff. intermediate, F. aff. ulna, Aulacoseira varians, Oedogonium sp., Ulothix sp. and Nostoc sp. were found. Among the protozoa, the first settlers were flagellates, followed by free-living bacteriophage ciliates that gave way to fixed ciliates (vorticelidos type). Temperature and conductivity were the variables that had a closer relationship with the algal fraction, unlike the bacterial fraction, which dominated at the beginning of the process. For protozoa, the pH was the most influential factor in the presence and abundance during succession, presenting dominance toward the final hours during the two limnological periods. The decline and appearance of new species of algae at the final hours of the colonization process, made evident a change in the structure of periphyton and a succession of the community in a span of 72 hours for this system in the Colombian Amazon.Instituto de Limnología "Dr. Raúl A. Ringuelet

A procedure to assess the spatial variability in the importance of abiotic factors affecting distributions: the case of world freshwater fishes

Understanding the factors shaping species' distributions is a key longstanding topic in ecology with unresolved issues. The aims were to test whether the relative contribution of abiotic factors that set the geographical range of freshwater fish species may vary spatially and/or may depend on the geographical extent that is being considered. The relative contribution of factors, to discriminate between the conditions prevailing in the area where the species is present and those existing in the considered extent, was estimated with the instability index included in the R package SPEDInstabR. We used 3 different extent sizes: 1) each river basin where the species is present (local); 2) all river basins where the species is present (regional); and 3) the whole Earth (global). We used a data set of 16,543 freshwater fish species with a total of 845,764 geographical records, together with bioclimatic and topographic variables. Factors associated with temperature and altitude show the highest relative contribution to explain the distribution of freshwater fishes at the smaller considered extent. Altitude and a mix of factors associated with temperature and precipitation were more important when using the regional extent. Factors associated with precipitation show the highest contribution when using the global extent. There was also spatial variability in the importance of factors, both between species and within species and from region to region. Factors associated with precipitation show a clear latitudinal trend of decreasing in importance toward the equator

Predicting the effects of climate change on future freshwater fish diversity at global scale

The aim of the present study was to predict future changes in biodiversity attributes (richness, rarity, heterogeneity, evenness, functional diversity and taxonomic diversity) of freshwater fish species in river basins around the world, under different climate scenarios. To do this, we use a new methodological approach implemented within the ModestR software (NOO3D) which allows estimating simple species distribution predictions for future climatic scenarios. Data from 16,825 freshwater fish species were used, representing a total of 1,464,232 occurrence records. WorldClim 1.4 variables representing average climate variables for the 1960¿1990 period, together with elevation measurements, were used as predictors in these distribution models, as well as in the selection of the most important variables that account for species distribution changes in two scenarios (Representative Concentration Pathways 4.5 and 6.0). The predictions produced suggest the extinction of almost half of current freshwater fish species in the coming decades, with a pronounced decline in tropical regions and a greater extinction likelihood for species with smaller body size and/or limited geographical ranges.We acknowledge institutional support from the Unit of Information Resources for Research at the Unit of Information Resources for Research at the "Consejo Superior de Investigaciones Científicas" (CSIC) for the article-processing charges contribution

Ecological Factors and Diversification among Neotropical Characiforms

Morphological and DNA sequence data has been used to propose hypotheses of relationships within the Characiformes with minimal comparative discussion of causes underpinning the major intraordinal diversification patterns. We explore potential primary morphological factors controlling the early diversification process in some Neotropical characiforms as the first step to identifying factors contributing to the pronounced intraordinal morphological and species diversity. A phylogenetic reconstruction based on 16S rDNA (mitochondrial) and 18S rDNA (nuclear) genes provided the framework for the identification of the main morphological differences among the Acestrorhynchidae, Anostomidae, Characidae, Ctenoluciidae, Curimatidae, Cynodontidae, Gasteropelecidae, Prochilodontidae and Serrasalmidae. Results indicate an initial split into two major groupings: (i) species with long dorsal-fin bases relative to the size of other fins (Curimatidae, Prochilodontidae, Anostomidae, Serrasalmidae) which primarily inhabit lakes, swamps, and rivers (lineage I); and (ii) species with short dorsal-fin bases (Acestrorhynchidae, Gasteropelecidae, Characidae) which primarily inhabit creeks and streams (lineage II). The second diversification stage in lineage I involved substantial morphological diversification associated with trophic niche differences among the monophyletic families which range from detritivores to large item predators. Nonmonophyly of the Characidae complicated within lineage II analyzes but yielded groupings based on differences in pectoral and anal fin sizes correlated with life style differencesThis study was supported by the AMAPEZ project (CGL2006-02155 BOS) of the MEC (Ministry of Education and Science) under FEDER funds from the XUNTA de Galicia and by contributions from the Universidad de Vigo, the Universidad de Antioquia, and the Universidad Nacional de Colombia. A. Manjarrés-Hernández gratefully acknowledges a grant from COLCIENCIASS