Incorporación de nitrógeno y fósforo por Sarcocornia perennis (Miller) A. J. Scott, en concentraciones reales en el estuario del río Palmones

Sarcocornia perennis (Miller) A. J. Scott es una Quenopodidácea dominante en las marismas saladas de Estuario del Río Palmones (España). Esta especie forma extensas y densas praderas las cuales actúan como sumidero de nutrientes entre la tierra y el mar. Se ha estudiado la capacidad de incorporar nutrientes en concentraciones reales encontradas en el medio por esta planta. Se ha obtenido la Vmax, Km, y Cmin para cada nutriente (NO−3, PO−34 y NH+4 ). El NO−3 se encuentra en concentraciones limitantes para la planta, pero esta deficiencia de nitrógeno es solventada por el NH+4 como fuente de nitrógeno. Las ventajas de Sarcocornia sobre otros macrófitos como Spartina (Spartina alterniflora and Spartina patens) son discutidasSarcocornia perennis (Miller) A. J. Scott is a Chenopodiaceae dominant in salt marshes of Palmones river estuary (Spain). It forms dense and extended meadows which act as an active nutrient sink between land and sea. The capacity of nutrient uptake has been studied at natural concentrations found in eld surveys. Vmax, Km, and compensation point (Cmin) for nutrients have been obtained for NO−3, PO−3 4 , and NH+4 . Nitrate is limitant for the plant, but the nitrogen deficiency is replaced by NH+4 as a nitrogen source. The advantage of Sarcocornia over other macrophytes such as Spartina (Spartina alterniflora and Spartina patens) has been discusse

Sustitución de comunidades y concentración de nutrientes en plantas tras incendios forestales en una cuenca subárida del S.E. de España

Specific plant communities replacement in a subarid basin (Sierra de Almijara, S.E. Spain) is described related with internal concentration of C, N and compartimental P in several post-fire representative and dominant species. Plots were burnt 1, 6, 12 and 30 years before respectively, because fire is a recurrent phenomenon in that mediterranean shrublands. Juniperus oxycedrus is typical of the advanced stages of succession and presents low concentration of P and N, specially in old plants. Genista spartioides minimizes C:N ratio due to its symbiotic activity; and Cistus clusii shows an active cumulative metabolism specially in that concerning the phosphorus retention. In the frame of the general theory of sucession, C . clusii takes advantages of its ability to internalize high concentration of phosphate and Fabaceae of N accumulation. A dilution effect is detected in plants which are characteristic of the vegetation at the end of recolonization.Se describe la sustitución de comunidades tras incendios en una cuenca subárida (Sierra de Almijara, S.E. España), en relación con las concentraciones de carbono, nitrógeno y varios compartimentos de fósforo en tejidos de 5 especies de plantas representativas, en parcelas incendiadas hace 1, 6, 12 y 30 años respectivamente. El fuego se presenta de modo recurrente en estos matorrales mediterráneos. Juniperus oxycedrus, propia de formaciones de monte alto y de etapas avanzadas de la sucesión, presenta bajas concentraciones de P y N, especialmente en plantas viejas. Genista spartioides minimiza el indice C:N debido a su actividad simbiótica; y Cistus clusii muestra un activo metabolismo acumulador especialmente en lo que se refiere a la retención de fósforo. En el marco de la teoria general de la sucesión, C.clusii obtendria ventajas de su habilidad para internalizar altas concentraciones de fosfato y especies de la familia Fabaceae de su capacidad de acumulación de nitrógeno. En plantas caractensticas de las fases finales de la recolonización, se ha detectado un efecto de dilución de 10s nutrientes internos a medida que transcurre el tiempo tras el incendio

Lutein and the C/N as tracers of organic matter in the Palmones River estuary

Los pigmentos vegetales han sido usados como bioindicadores de la presencia de organismos fototrópicos en ríos, estuarios y sedimentos marinos actuales y en estudios paleolimnológicos. En el sedimento del estuario río Palmones (Bahía de Algeciras, Sur de España) se ha estudiado las concentraciones de clorofila a y luteína, el índice C/N y el contenido en materia orgánica. Utilizando la concentración de estos dos pigmentos en diferentes profundidades así como el índice de sedimentación(determinado por Rubio et al. En 2003 por el método del 210Pb), se ha determinado el índice de degradación de la luteína y clorofila a en la marisma. La permanencia de la luteína en el sedimento es mayor que la de la clorofila a. Según estos resultados se ha podido discriminar las fuentes de materia orgánicaPlant pigments have been used as biomarkers of the presence of phototrophic organisms in rivers, estuaries and sea sediments in present and in paleolimnological studies. Chlorophyll a and lutein concentration, C/N ratio and organic matter content have been studied in the sediment of the Palmones River estuary (Algeciras Bay, Southern Spain). Using the concentration of these two pigments at different depths, as well as the sedimentation rate (determined by Rubio et al. in 2003 by means of the 210Pb method), lutein and chlorophyll a degradation rate has been determined, in the saltmarsh. Lutein persistence in the sediment was higher than the persistence of chlorophyll a. According to these results, it was possible to discriminate the organic matter source

Análisis de componentes principales sobre datos multiespectrales “Landsat-TM” e interpretación de cubiertas vegetales en las Sierras de Tejeda y Almijara

The simultaneous consideration of all reflectance bands during image processing of multiespectral, remotely-sensed data, usually involves a very large volume of data to handle. However, this increase in data volume is not followed by a similar increment in the volume of additional information that is accounted for, which is due to the existence of a very high correlation between reflectance bands. In this paper we report the results of applying a multivariate statistical tool (Principal Component Analysis, PCA) to the first four reflectance bands of a LANDSAT «Thematic Mapper» image of Sierra de Tejeda and Sierra de Almijara (Southern Spain). The aim of this analysis was to achieve a reduction in the volume of data to handle during image processing while avoiding a significant loss of information. The first two principal components resulting from the analysis accounted for more than 99% of the total variance in the original data set. The image obtained through the first principal component transform could be interpreted as a weighed-sum image of all reflectance bands (thus similar to a black and white panchromatic photograph with an extension into the infrared wavelength). This image showed optimum feasibility for the interpretation of geological, hydrological and topographic features of the study area. The second principal component transform was able to extract the «green» signal of the vegetation canopy from the complex set of multiespectral data. Relief features (i.e., areas of shadow in north-facing slopes versus well-illuminated, south-facing slopes) did not appear in the resulting image (these features had already been accounted for by the first principal component), which is an advantage when studying vegetation cover in areas with steep relief. A strong possitive correlation was found between the second PCA image and those resulting from the application of standard spectral vegetation indexes (RVI and NDVI). The initial assesment of the images has shown that severe deaforestation is undergoing in the area. About 30% of the study area was occupied by bare soils. This figure went up to 85% if areas with scattered vegetation were also included. Multivariate analysis has confirmed as a valuable tool for the interpretation of multiespectral satellite data from the study area. Eventually, the obtention of a principal component transform based on the selective sampling of appropiate subsets of pixels from the area would provide of algorithms that applied to the entire set in multitemporal images could, for instance, be used to monitor long-term and large-scale deaforestation processes in the region.La consideración simultánea de todas las bandas de reflectancia en el análisis de imágenes multiespectrales teledetectadas, representa un incremento en el volumen de datos a procesar proporcionalmente mucho mayor que la ganancia real de información que se consigue, lo que se debe a la elevada correlación existente entre aquéllas. En este trabajo se aplica un análisis de componentes principales a datos multiespectrales Landsat TM de las Sierras de Tejeda y Almijara, con el objeto de sumarizar los mismos sin una pérdida significativa de información. Los dos primeros componentes principales obtenidos recogieron más del 99% de la varianza total original. La imagen que se obtuvo a partir del primer componente principal representaba, aproximadamente, una suma ponderada de todas las intensidades de reflectancia en las distintas bandas consideradas (análoga, por tanto, a una fotografía en blanco y negro con una extensión en el infrarrojo) y mostró una interpretabilidad óptima para aspectos de topografía-relieve, red de drenaje y tipos litológicos. La imagen resultante del segundo componente principal (ya sin efecto de relieve) mostró la intensidad de señal "verde" del dosel vegetal y se correlacionaba significativamente con las obtenidas de la aplicación de índices espectrales de vegetación (RVI, NDVI) a los datos originales. El análisis preliminar de las imagenes indica problemas de deforestación grave en la zona (casi un 30% de la superficie con suelos desnudos, y hasta un 85% si se incluyen areas con vegetación dispersa). El análisis multivariado se ha confirmado como una herramienta útil para la interpretación de imágenes teledetectadas de la zona de estudio. Eventualmente, la obtención de la transformación de componentes principales por medio de un muestreo selectivo, proveería de algoritmos de transformación para los datos multiespectrales con los que se podría, por ejemplo, hacer un seguimiento de cambios en procesos tales como la deforestación

Mobile radio interferometric geodetic systems

Operation of the Astronomical Radio Interferometric Earth Surveying (ARIES) in a proof of concept mode is discussed. Accuracy demonstrations over a short baseline, a 180 km baseline, and a 380 km baseline are documented. Use of ARIES in the Sea Slope Experiment of the National Geodetic Survey to study the apparent differences between oceanographic and geodetic leveling determinations of the sea surface along the Pacific Coast is described. Intergration of the NAVSTAR Global Positioning System and a concept called SERIES (Satellite Emission Radio Interferometric Earth Surveying) is briefly reviewed

Relationship between physicochemical variables and productivity in open ponds for the production of Spirulina: a predictive model of algal yield,”

Abstract Spirulina is one of the most extensively used microalgae for animal and human nutrition; its main interest is centered in its high protein content, 60 -65% on a dry weight basis. In this study, Spirulina was grown in open raceway ponds, and several physicochemical (e.g., pH, dissolved oxygen concentration, temperature, conductivity and irradiance) and biological (e.g., biomass concentration and yield) variables were studied. The variables were correlated in order to implement a mathematical model to predict algal yield. Dissolved oxygen concentration in the cultivation ponds ranged between 10 mg l À 1 in winter (115% of O 2 saturation) and 30 mg l À 1 in summer (375% of O 2 saturation); a clear decrease of biomass concentration was found when dissolved oxygen was >25 mg l À 1 . Neither biomass concentration nor productivity was saturated at the maximum temperature achieved in the open pond during this study (approximately 28 jC). The pH seemed to control both the maximal algal density in the pond and the productivity that were found to be maximum at pH values below 10.5. Finally, all the variables were positively correlated with irradiance. Principal component analysis (PCA) allowed recognition of different sets of samples characterized by a combination of temperature, dissolved oxygen concentration, pH, biomass, productivity, irradiance and conductivity. This method helped to predict a significant loss of productivity in the open ponds in mid-summer due to high pH and high-dissolved O 2 concentration.