Influencia de la ruptura de la termoclina sobre la comunidad de rotíferos planctónicos de una laguna meromíctica (Las Madres, Madrid)

Diez páginas, 9 figuras y 2 tablas. Los autores quieren señalar: "AGRADECIMIENTOS - A Angel Baltanás y María Valladolid que participaron en la «interminable» toma de muestras y en la realización de los análisis."[EN] Las Madres Lake is a shallow, oligo-mesotrophic, gravel-pit lake close to Madrid (Spain). In this paper we report the influence of the summer stratiphication-autumm overturn transition on the rotifers community. The existence of oxycline and anoxic hypolimnion explain the presence of Anuraeopsis fissa and Fi/inia holmanni: these species can colonize the environments where the oxygen concentration is very low. Polyarthra spp. and Hexarthra spp. are the main species.[ES]Desde finales de verano hasta mediados de otoño de 1991 se tomaron muestras, diariamente, en una laguna de gravera próxima a Madrid. Se determinaron diversos parámetros físico-químicos a partir de muestras tornadas a diferentes profundidades en la zona pelágica. La desaparición de la temoclina tuvo lugar lentamente manteniéndose constantemente una fuerte oxiclina que discriminará claramente la distribución vertical de las diferentes especies de rotíferos planctónicos, de las que solo seis de ellas: Polyarthra dolichoptera, P. remata, Hexarthra oxyuris, H. mira, Anuraeopsis fissa y Filinia hofmanni, representan el 98% de la densidad total de población. Este trabajo aporta información detallada de los cambios que se producen en la estructura de la comunidad de rotíferos cuando desaparece la estratificación térmica del verano y aumenta la profundidad de la zona de agua mezclada del epilimnion. El período de tiempo de este estudio se prolongó durante tres meses.CSIC- Museo Nacional de Ciencias NaturalesCSIC- Centro de Ciencias MedioambientalesPeer reviewe

Estudio limnológico de seis medios leníticos de La Rioja (España)

17 páginas, 5 figuras y 7 tables[EN] Seasonal limnological samples in six waterbodies from La Rioja (Northern Spain) were taken during a year (july 1996-May 1997). Different saliniry and eutrophication levels were found. 90 phytoplankton, 45 rotifers and 56 macrozoobenthic taxa were identified. All environments weee shallow lakes, lying on a Tertiary valley, most of them experiencing high turbidity. Most phyroplankton algae were new records for the area. Likewise, all macrozoobenthic taxa were new records for La Rioja. Brachionus leydigi f. tridentatlts (Sernov, 1901), Keratella cochlearis var hispida Lauterborn 1900 and Euchfanis alata Voronkov 1912 were new rotifer records for Spain.[ES] A 10 largo de un ciclo anual, entre julio de 1996 y mayo de 1997, se llevó a cabo el estudio limnológico de seis medios acuáticos de La Rioja, con una periodicidad estacional. En estos medios, con una acusada variabilidad en su contenido de sales disueltas (desde hipersalinos a dulces) y elevados niveles de eutrofización, en general, se han identificado 90 taxa de fitoplancton, 45 de rotíferos y 56 de organismos macrozoobentónicos. Dada la escasez de estudios sobre las algas en La Rioja, prácticamente todas las especies encontradas son nueva cita para la zona, si bien en España son todas bastante comunes en ambientes análogos. Así mismo, los organismos macrozoobentónicos encontrados son nueva cita para La Rioja. Los rotíferos Brachionus leydigi f. tridentatlts (Sernov, 1901), Kerateffa cochlearis var hispida Lauterborn 1900 y Euchfanis alata Voronkov 1912 son nuevas citas para España.Peer reviewe

Daily variations in the optical properties of a small lake

13 pages, and figures, and tables statistics1. The major components of the underwater light field (ULF: vertical attenuation, absorption, scattering and suspensoids including plankton fractions) of Las Madres Lake, a small wind-sheltered, oligohumic lake in Central Spain, were investigated daily over a period of 3 months at the onset of vernal circulation. 2. Gilvin, arising mostly from the decomposition of reeds in the littoral in autumn, was the main component of vertical attenuation, and its variability explained the highest fraction of absorption variability. Tripton appeared to be the main factor responsible for scattering, and might have resulted from dust deposition from the surrounding mining land. The plankton community played a minor role in attenuation, absorption or scattering throughout the investigation period. 3. Vertical and horizontal mixing dynamics may control the ULF to a certain extent, as most optical properties changed within different mixing periods and poor advective exchanges may have resulted in uneven distribution of water colour in this small lake. 4. Time series analysis showed that most autocorrelations were shorter than a week, inherent properties (absorption, scattering) being delayed longer than apparent properties (attenuation, transparency) as a result of their lower dependence on solar irradiance. A 2-day lag was observed in cross-correlations between either gilvin and absorption or tripton and scattering. When different mixing periods at early circulation were considered, however, ULF components changed their relationships and delays with suspensoids and dissolved substances over such periods, probably tracking the dynamics of their controlling factors. 5. Our study, and others at daily, weekly, seasonal, interannual and long-term scales, demonstrates that ULF is a system upon which different processes are operating at different time scales. Contrary to expectations, however, the variability in the ULF does not increase with time scale and depends partly upon the trophic status of lakes.Peer reviewe

Aquatic environments in Las Rozas de Madrid (Central Spain), Part 2: Surface- and groundwaters, leisure areas and fountains

Convenio firmado entre el Excelentísimo Ayuntamiento de Las Rozas y el CSIC y que se titula Gestión local sostenible en el ámbito de la Política de Aguas.[EN] Urban ecology has seldomly been tackled in Spain. This book is devoted to compile data and some preliminary analyses in aquatic environments of Las Rozas de Madrid (Central Spain), the third income-per-capita city in Spain which has some 50% of impervious surfaces throughout its area. Las Rozas encompasses many examples where water is the basic resource. Streams, stagnant waterbodies including leisure environments, fountains, wastewater treatment plants and groundwaters are the main ones. Our studies undertaken in the last decade and a half have provided us with information on the structure and function of these environments, some of which are interesting for their own sake. What cannot be overlooked is the the main controlling factor of their functioning is urbanization, which acts changing surficial runoff because of the high amount of impervious surfaces and strong discharges of partially treated, urban wastewater. This study is complementary of those by Alvarez-Cobelas et al. (2005), Martín-Fernández et al. (2010) and Vicente-Sánchez (2010).[ES] Este estudio refiere los datos y resultados obtenidos fundamentalmente en el curso del año 2013 dentro del Convenio firmado entre el Excelentísimo Ayuntamiento de Las Rozas y el CSIC y que se titula Gestión local sostenible en el ámbito de la Política de Aguas. Sin embargo, también es un resumen de todos los datos acuáticos generados por nuestro equipo desde el año 2000 hasta el 2013 en ese término municipal. Los trabajos realizados durante 2013 abarcan diversos aspectos relacionados con la calidad del agua en el Municipio: la calidad del agua de ríos y arroyos que discurren por el término municipal, la calidad del agua de dos espacios de ocio (el Canal de la Dehesa de Navalcarbón y los estanques del Parque París), la calidad de las aguas subterráneas y la calidad de las aguas de las fuentes ornamentales. Finalmente, se incluye también un estudio sobre la ecología de los ecosistemas estancados del municipio, comparándola con la observada hace diez años y recogida en el informe correspondiente y en el libro de Alvarez Cobelas et al. (2005). No son frecuentes en España los estudios sobre la ecología de los espacios periurbanos, quizá porque los ambientes naturales –degradados o no– siempre resultan más atractivos para el biólogo y el ecólogo. Y, sin embargo, la vocación netamente urbana de nuestra civilización hace que, cada vez más, los ecosistemas donde residimos y su salud ambiental cobren mayor importancia. Otras sociedades de mayor renta per capita prestan mayor atención a esa clase de ecología (véanse, por ejemplo, los trabajos de Pickett et al. 2001, Paul & Meyer 2001, Chin 2006, Iwata et al. 2007 y Grimm et al. 2008). En este trabajo hemos pretendido facilitar datos con vistas a un futuro estudio global sobre el agua en los ambientes urbanos de nuestro país. La tesis doctoral de Juan Vicente Sánchez (2010) resulta un valioso complemento de este trabajo. Finalmente, este libro puede considerarse complementario del de Martín Fernández et al. (2010)

Zooplankton dynamics during autumn circulation in a small, wind-sheltered, Mediterranean lake

12 pages, and tables statistics.Few studies have been undertaken on zooplankton dynamics during the transition from late stratification to early mixing in lakes. The Plankton Ecology Group (PEG) model of plankton seasonality only considers water temperature, edible phytoplankton and fish predation as zooplankton-controlling factors during that period. The water-column edible algal and bacterial fractions, heterotrophic nanoflagellates, ciliates, rotifers, cladocerans and copepods were studied during 93 consecutive days of mixing-transition in a wind-sheltered, Mediterranean lake without planktivorous fish. Abundances of all zooplankton populations except ciliates, Daphnia longispina and copepodites, were related to water temperature. In addition to PEG controlling factors, time series analysis indicated competition between ciliates and Ceriodaphnia reticulata and Polyarthra dolichoptera and D. longispina, predation of Arctodiaptomus salinus on ciliates, herbivory of adult copepods on the 5–20μm phytoplanktonic size and delayed effects shorter than oneweek.The remaining zooplankton populations did not showany edible size preference. Ceriodaphnia reticulata showed evidence of herbivory on bacteria and picoplankton and competition with Hexarthra fennica in shorter periods. Phyto- and zooplankton production were decoupled. These results, and others from warmer periods and latitudes, suggest that the current model of lake plankton seasonality must be reviewed.Peer reviewe

Daily patterns of mixing and nutrient concentrations during early autumn circulation in a small sheltered lake

17 pages, 11 figures, 1 table.-- Printed version published May 2005.1. Autumn circulation in lakes is currently conceived to occur very rapidly, being controlled mainly by wind-power dynamics, decreasing irradiance and heat flux. In addition, autumn mixing is usually related to nutrient redistribution in the vertical column, resulting in its overall increase. To test these assumptions, mixing and nutrient dynamics in a Spanish small, wind-sheltered, mesotrophic, seepage lake were studied daily during autumn circulation.2. The seasonal erosion of the pycnocline in Las Madres Lake was the outcome of vertical and horizontal exchanges of heat and matter. The overall mixing of the water column lasted 3 months, which was an unexpected period for a rather shallow lake. Two periods of mixing could be envisaged until full circulation was attained. First, a slightly faster period of pycnocline deepening than that predicted by the heat flux and wind stress model of Fisher et al. (1979) occurred for 41 days, mixing most of the water column down to within two meters of the bottom. Then a much slower process took place promoting frequent instability of the bottom layer and resulting in entire mixing in a further 52 days.3. Vertically, the whole mixing process was a response to weak surface cooling, resulting from the mild air temperatures of the semiarid climate of the area, and weak wind stress, because of low wind fetch and high shelter. Horizontally, a gravity current transporting cold, denser water from western shallower areas of the lake and materials produced by the decomposition of organic matter of littoral origin may produce a bottom layer of increased density, thus impinging on vertical stability. Seepage inputs of water of roughly constant temperature might also have increased bottom density. Bottom density enhancement resulted in a double diffusion process.4. Only in-lake nitrogen content increased until full circulation was attained, whereas carbon showed no trend and phosphorus declined. External processes, such as seepage exchange and atmospheric deposition, coupled to internal processes, such as nitrification, oxidised phosphorus precipitation and complexation with organic carbon, might have been responsible for the areal nutrient patterns observed.5. Our study demonstrates that current models of water column mixing and nutrient redistribution in lakes during autumn circulation must be improved to encompass the effects of external inputs, including horizontal heat and matter exchange.Peer reviewe

The role of charophytes in a Mediterranean pond created forrestoration purposes

A small, shallow basin was created and flooded with groundwater in a Reserve Area in Albufera de València Natural Park (AVNP) under the scope of a restoration program intended to mimic typical environments such as freshwater springs, abundant in the past but currently suffering from deterioration (desiccation, pollution, etc.), with the ultimate goal of increasing local biodiversity of submerged macrophytes, particularly charophytes. In this study we have monitored, from April 2009 (a few months after its first flooding) to September 2012, the dynamics of charophyte growth and related physical, chemical and biotic variables to highlight the factors determining charophyte success. Just after flooding, five charophyte species grew spontaneously when oospores germinated in the sediments. Chara hispida populations largely dominated the community and developed dense meadows that covered virtually the entire pond floor. Charophytes exerted a negative influence on phytoplankton densities, increasing water transparency. C. hispida stands precipitated substantial CaCO3 in the form of incrustations on the plants, accompanied by coprecipitation of inorganic phosphorus, maintaining low concentrations of soluble P in the water. Reduced groundwater inflow, increased salinity, nutrient concentration, turbidity and augmented feeding pressure by waterfowl, separately or by synergistic effects, considerably reduced charophyte development during the final year of the study; however, charophytes still represent one of the most extensive and dense stands of submerged vegetation within AVNP, verifying the achievement of the goal of the restoration plan. The knowledge obtained has allowed us to recommend several measures to counteract the decrease of charophytes, which can also be applied in other regions affected by the same stressors. © 2014 Elsevier B.V. All rights reserved.The authors express thanks for the funding of this study by TRAGSA and Confederacion Hidrografica del Jucar (J. Ferrer, T. Estrela, M. Regidor) and by the Spanish Ministry of Economy and Competitiveness (research project CGL2009-10292, including plan E). We also thank Fidel Rubio, Jara Garcia-Chicote, Fran Cortes, Sara Calero and William Colom for their help during field and laboratory work. We also thank Matthieu Lassalle, Lucia Moreno and Lurdes Ribera (Tancat de la Pipa staff), particularly for providing data on inflows and water depth. We are grateful for the collaboration of the other members of the research group from Instituto de Ingenieria del Agua y Medio Ambiente (Polytechnic University of Valencia) and of Mario Gimenez from SEO/Birdlife. The waterfowl censuses were part of the SEO/BirdLife's Bird Monitoring Program in AVNP, supported by the Alas sobre Agua Project and with the valuable help of many volunteers. Joan M. Benavent facilitated the aerial photography of the pond. Dominique Auderset-Joye made constructive comments on the manuscript. American Journal Experts carefully reviewed the English language of the manuscript.Rodrigo, MA.; Rojo, C.; Segura, M.; Alonso Guillén, JL.; Martín Monerris, M.; Vera García, P. (2015). The role of charophytes in a Mediterranean pond created forrestoration purposes. Aquatic Botany. 120:101-111. doi:10.1016/j.aquabot.2014.05.004S10111112