Miguel Álvarez Cobelas

Spanish National Research Council | CSIC · National museum of natural history

Muchas especies de mosca negra (Diptera, Simuliidae) son causantes de picaduras en humanos y en ganado, con importantes consecuencias desde el punto de vista médico y veterinario, principalmente cuando son vectores de diferentes enfermedades infecciosas. En este trabajo hemos abordado la importancia que tienen los macrófitos acuáticos presentes en...

Durante las últimas décadas se han fonnulado explícitamente varias hipótesis sobre el funcionamiento de las comunidades pelágicas lacustres en relación con el enriquecimiento en fósforo. Entre ellas, se cuentan: la) la relación directa eqtre fósforo y biomasa planctónica, za) los máximos de la riqueza específica planctónica a niveles intennedios de...

Aquatic ecology an society of Ruidera Lakes (Central Spain)

A study of chytrid infection on a wild phytoplankton population of the colonial species Fotterella tetrachlorelloides (Chlorophyceae, Oocystaceae) living in an eutrophic reservoir (El Vellón, Madrid) during the stagnation period has been undertaken. A dramatic decay of the Fotterella population was seen in connection with fungal development on it,...

Relationships between groundwater and lake ecology are often overlooked, but they may be strong, particularly in seepage lakes. As a result, the nature and degree of groundwater effects on lakes are usually neglected. In this study interactions among rainfall, groundwater and surface water and their limnological effects were traced seasonally for t...

A pesar de la relación obvia entre las aguas subterráneas y las superficiales, sólo algunos estudios han considerado indirec/Dmente los efectos que las primeras pueden tener sobre los limnosistemas españoles, aunque haya numerosas sugerencias de que tales efectos puedan ser importantes. Aquí presento una breve revisión de dichos efectos, los cuales...

Charophytes are submerged macrophyte algae often found in diverse aquatic habitats. Chara-dominated lakes are typically hard water, calcium-rich and low in phosphate. La Colgada is a 18 m deep, 103 ha small lake located in a tourist area, which has partly resulted in nutrient increases in recent years. Chara hispida var. major (Hartm.) R.D. Wood an...

The current ecosystem paradigm in limnology is represented by the cold temperate, stratifying lake and the single-channelled river. However, the variety of inland water ecosystems is much higher, and so is the ecological complexity of many of them. Most Mediterranean limnosystems are quite distinct from the contemporary limnological paradigm. This...

Several hypotheses have been outlined on the relationship of lake communities and phosphorus enrichment in recent years. Some of them are the following: i) a positive relationship between phosphorus and planktonic biomass, ii) species richness peaks at intermediate phosphorus concentrations, iii) the destabilisation of food web functional groups ar...

Este es el primer estudio que se realiza en España sobre la descomposición de la hojarasca de Cladíum mariscus (masiega) y Phragmites australis (carrizo) en un humedal hipertrófico mediterráneo, el Parque Nacional Las Tablas de Daimiel, en el que se realizaron dos experimentos de descomposición con hojas de las dos especies. Las hojas se introdujer...

The phytoplankton communities of thirteen adjacent gravel-pit lakes in the lower Jarama river watershed (Madrid, Spain), were studied during spring mixing and summer stratification. If different seasons, the phytoplankton responded to different environmental factors. During spring, the abundance of SRP (soluble reactive phosphorus) and existence of...

Coupling of multivariate methods and time series analysis can be ueful for studying dynamics of aquatic communities. This is demonstratred with a data set from the pelagic area of an oligo-mesotrophic lake in Central Spain during 61 consecutive days of Autumn overturn. Abiotic variables, phytoplankton species and their total biomass were traced. Sp...

A cross-system, worldwide approach has been used to ascertain the spatial, seasonal and long-term variability of areal phytoplankton photosynthesis (PP) in lakes using published data sets. Also, the average fraction of annual PP occurring under ice is calculated. The lakes considered embrace a range of properties (depth. mixing, flushing rate, lati...

Phytoplankton species groups were studied in a eutrophic reservoir at different time scales (daily, weekly, monthly and yearly). Four strategic groups along the r-K continuum were defined and their seasonal time courses were followed. Their temporal distribution of relative biomass reflected resource partitioning because each strategic group domina...

A structural analysis of river phytoplankton has been carried out based upon published studies on 67 rivers. When available on a yearly basis to account for seasonal variability, five structural features have been chosen: species composition, species richness, species dominance, diversity and biomass (total and per taxonomic groups). Despite the hi...

Populations of Limnothrix redekei, Oscillatoria lanceaeformis, Planktothrix agardhii and Pseudanabaena limnetica were found in a hypertrophic, gravel-pit lake near Madrid (Spain), throughout a one year sampling at weekly intervals. Physico-chemical factors, phytoplankton biomass and net growth rates were measured. Oscillatoria lanceaeformis was onl...

Weekly studies of phytoplankton biomass and environmental variables were made over one year in a shallow stratifying, hypertrophic El Porcal lake near Madrid (Spain). Data were collected on abiotic factors, primary production, biomass and phytoplankton losses and subjected to reduction by means of several principal component analyses. Furthermore,...

SEASONAL RESPONSE OF THE PHYTOPLANKTON COMMUNITY IN A EUTROPHIC RESERVOIR The seasonal changes of the phytoplankton community in a temperate monomictic, eutrophic reservoir (El Vellón, Madrid, Spain) have been studied as related to the driving environmental variables throughout an entire year. Phytoplankton community responded to seasonality-depend...

The provisions of Connell’s Intermediate Disturbance Hypothesis (IDH) were investigated in relation to the behaviour of freshwater phytoplankton in a hypertrophic lagoon, paying special attention to the link between species-diversity and environmental disturbances. Phytoplankton diversity yielded different indices depending on the basic unit of cal...

The seasonal time course of phytoplankton primary productivity was studied weekly in a hypertrophic, gravel-pit lake close to Madrid, Spain. Chlorophyll a ranged 22-445 mg m-2. Gross primary productivity attained 0.28 +/- 0.14 g C m-2 h-1 (range: 0.06-0.60), its yearly value being approximately 900 g C m-2, but the shallow euphotic depths and the h...

The phytoplankton of a hypertrophic lake close to Madrid (Spain) was sampled weekly throughout a year. The size biomass spectrum seems to be characterized by: 1) the greatest diversity of taxa occurs in nannoplankton size ranges, 2) discontinuities in the presence of microplankton, 3) variability in the frequency distribution of nannoplankton, 4) t...

Commercial seaweeds in Spain are harvested on the north and northwest coasts. They are mainly agarophytes and carrageenophytes (Gelidium spp. and some Irish moss-like species, respectively), although some Phaeophyceae species (Fucus spp. and Laminaria spp.) are also exploited for alginates. No industrial seaweed cultivation is carried out in Spain...

A population of Nitzschia gracilis was studied with weekly sampling over 8 months in a hypertrophic gravel pit lake near Madrid, Spain. Sedimentation losses were measured and net growth rates were calculated. Physical factors (incoming solar radiation, vertical attenuation coefficient, water temperature, Zeu:Zm ratio and the Brunt-Väisäla frequency...

Commercial seaweeds in Spain are harvested on the north and northwest coasts. They are mainly agarophytes and carrageenophytes (Gelidium spp. and some ‘Irish moss’-like species, respectively), although some Phaeophyceae species (Fucus spp. and Laminaria spp.) are also exploited for alginates. No industrial seaweed cultivation is carried out in Spai...

Some features of the chemical limnology of a hypertrophic, gravel-pit lake close to Madrid (Spain) have been studied at weekly intervals through out a year. El Porcal Lake in an alkali ne, slightly saline, water body without surface inflow or outflow. Anoxia is a common feature below the 2 m level from May to September. Dissolved oxygen oversaturat...

A biogeography of the Iberian seaweed flora is proposed, based upon records published by different authorities up to Jury, 1987. The Iberian Península compases two distinct provinces, namely the Atlantic Iberia and the Mediterranean Iberia, having six biogeographic sectors: Guipúzcoa, the Cantabrian Sea and the Galician shelf, Northern Portugal, So...

En este trabajo se realiza una revisión bibliográfica sobre la Biotecnología de las Algas. Esta consiste en el cultivo masivo de las algas en condiciones controladas con objeto de usar posteriormente la biomasa producida. La revisión empieza con una breve reseña histórica y continúa describiendo las necesidades del cultivo masivo: inóculo, tecnolog...

A catalogue of Spanish blue�green algae/Cyanobacteria up to July 1981 is given. 554 tuca are reported. EN: Se refiere aquí un catálogo de las Cianoficeas/Cianobacterias españolas citadas hasta julio de 1981, las cuales ascienden a 554 táxones.

Se ha estudiado el impacto de una infección por hongos Chytridiales (Phycomycetes) sobre una población del alga Oocystis borgei (Chlorophyceae, Oocystaceae) localizada en un embalse eutrófico (El Vellón, Madrid) durante el período de estratificación. El proceso de infección se desarrolla en condiciones ligeramente elevadas de pH y temperatura. La c...

SUMMARY 1. Measurements of daily growth rates, colony widths and lengths and cell widths and lengths were made on Fotterella tetrachlorelloides Buck and Staurastrum longiradiatum West & West (Chlorophyceae), collected from an eutrophic reservoir close to Madrid (Spain) on nine consecutive days of June 1983. 2. F. tetrachlorelloides exhibited growth...

Se ha estudiado el impacto de una infección de hongos Chytridiales (Phycomycetes) sobre una población natural del alga cenobial Fotterella tetrachlorelloides (Chlorophyceae, Oocys-taceae) localizada en un embalse eutrófíco (El Vellón, Madrid) durante el período de estrati-ficación. Con el desarrollo de la infección se observa un descenso drástico d...

A catalogue of Spanish inland algae belonging to Chlorophyceae (557 taxa) and Prasinophyceae (9 taxa) and found up to July 1981 is given. En este trabajo se refieren las algas continentales citadas para España hasta julio de 1981 pertenecientes a los grupos Chlorophyceae (557 tazones) y Prasinophyceae (9 tazones).

Bibliografía de botánica

Los humedales son poco conocidos comparados con otros ambientes de la Naturaleza madrileña. Esta revisión es una introducción a la ecología de estos ecosistemas, donde se describen someramente los conocimientos actuales sobre ellos y se señalan las carencias de información. Los humedales madrileños comparten muchas características con los de clima...

En un agua procedente de un tratamiento biológico secundario con lodos activos se inoculó un cultivo mixto de Chlorella saccharophila y Scenedesmus acutus que creció en discontinuo en sendas cubetas a 25ºC y a 30ºC, respectivamente (iluminación 11 klux; fotoperiodo, 15/9), determinándose los siguientes parámetros: clorofila a, densidad óptica a 560...