El género Mastogloia en los sistemas acuáticos del litoral mediterraneo español

Desde 1979 se ha estudiado la flora de diatomeas bentónicas de 60 ecosistemas acuáticos del litoral mediterráneo español. En este trabajo se resumen las observaciones realizadas sobre las especies del género Mastogloia Thwaites presentes en estos puntos. Se han identificado 18 especies y 4 variedades; 15 de las cuales se citan por primera vez de nuestras aguas epicontinentales. Los datos sobre la distribución de las frecuencias relativas (%) de cada uno de los táxones del género Mastogloia han permitido la tipificación de las localidades estudiadas. Esta clasificación está de acuerdo con la obtenida a partir de los datos sobre la mineralización de las aguas (LOPEZ, 1981b).

Effects of riparian vegetation removal on nutrient retention in a Mediterranean stream

We examined the effects of riparian vegetation removal on algal dynamics and stream nutrient retention efficiency by comparing NH4-N and PO4-P uptake lengths from a logged and an unlogged reach in Riera Major, a forested Mediterranean stream in northeastern Spain. From June to September 1995, we executed 6 short-term additions of N (as NH4Cl) and P (as Na2HPO4) in a 200-m section to measure nutrient uptake lengths. The study site included 2 clearly differentiated reaches in terms of canopy cover by riparian trees: the first 100 m were completely logged (i.e., the logged reach) and the remaining 100 m were left intact (i.e., the shaded reach). Trees were removed from the banks of the logged reach in the winter previous to our sampling. In the shaded reach, riparian vegetation was dominated by alders (Alnus glutinosa). The study was conducted during summer and fall months when differences in light availability between the 2 reaches were greatest because of forest canopy conditions. Algal biomass and % of stream surface covered by algae were higher in the logged than in the shaded reach, indicating that logging had a stimulatory effect on algae in the stream. Overall, nutrient retention efficiency was higher (i.e., shorter uptake lengths) in the logged than in the shaded reach, especially for PO4-P. Despite a greater increase in PO4-P retention efficiency relative to that of NH4-N following logging, retention efficiency for NH4-N was higher than for PO4-P in both study reaches. The PO4-P mass-transfer coefficient was correlated with primary production in both study reaches, indicating that algal activity plays an important role in controlling PO4-P dynamics in this stream. In contrast, the NH4-N mass-transfer coefficient showed a positive relation-ship only with % of algal coverage in the logged reach, and was not correlated with any algal-related parameter in the shaded reach. The lack of correlation with algal production suggests that mechanisms other than algal activity (i.e., microbial heterotrophic processes or abiotic mechanisms) may also influence NH4-N retention in this stream. Overall, this study shows that logging disturbances in small shaded streams may alter in-stream ecological features that lead to changes in stream nutrient retention efficiency. Moreover, it emphasizes that alteration of the tight linkage between the stream channel and the adjacent riparian zone may directly and indirectly impact biogeochemical processes with implications for stream ecosystem functioning.

Fluctuaciones de varios años de período medio en la producción de fitoplancton en el mediterraneo occidental

Las posibilidades de explotación de cualquier ecosistema no sólo dependen de su producción primaria o básica (a nivel de los vegetales), sino también de cómo los valores de dicha producción en las distintas temporadas se distribuyen alrededor de la media general. Si su dispersión es muy grande, es decir, cuando ciertos años son enormemente productivos y otros muy poco, las condiciones de explotación son distintas de otra situación en la que, año tras año, se repiten aproximadamente las mismas cifras de producción.

Sobre la actividad antibiotica de ciertas especies de algas del Mediterraneo

El estudio de la actividad antibiótica de las algas se halla actualmente en pleno auge, y existe información bibliográfica en relación con esta actividad de gran número de especies que también existen en nuestras costas. En el presente trabajo se pretende abrir esta línea de investigación para confirmar o descubrir la referida actividad en nuestras poblaciones.

Noves citacions de Chondrymenia lobata (Meneghini) Zanardini i Laminaria rodriguezii Bornet per a la Peninsula Iberica

Noves citacions de Chondrymenia lobata (Meneghini) Zanardini i Laminaria rodriguezii Bornet, per a la Peninsula Ibèrica PAÍS VALENCIA: Peniscola, entre 100-120 braces de profunditat, a les xarxes dels pescadors (14-6-1983).

Preliminary report of the first season work of the International Pluridisciplinary Archaeological Expedition to Bactria 2007

A prior long-term and complex evaluation of the already available data on the geophysical prospecting during the first season work carried out at 2006, at the archaeological site of Tchinguiz Tepe of Termez, took place to decide the strategy to follow during the campaign of 2007. This previous evaluation of the information, on one hand, leaded to the decision to increase the geophysical prospecting at Tchinguiz Tepe, on the other hand, to decide the exact location of areas where the archaeological interventions.would carry out. The main objective at the beginning of this new season was to crosscheck the reliabilityof the measurements and, at the same time, to establish the unknown up to the present archaeologicaland chronological sequence of Tchinguiz Tepe. Meanwhile, the geophysical prospecting also wasextended to the outskirts of the city were the localisation of an unknown up to now Buddhist Monasterywas possible.

Preliminary report of the first season work of the International Pluridisciplinary Archaeological Expedition to Bactria 2006

The International Pluridisciplinary Archaeological Expedition in Bactria (IPAEB) was created in 2006.The name underlines the international character of the team (which includes Uzbeks, Spanish, French, British and Greek members), the presence of specialists from various fields apart from archaeology and the fame of Bactria1.

Preliminary report of the first season work of the International Pluridisciplinary Archaeological Expedition to Bactria 2008

This year the development of our project can be divided into two main clearly different parts, on one hand the laboratory work, where the sampled ceramic individuals has been prepared and analyzed and the elaboration of the data obtained during the excavation of 2007 has been finished and, on the other hand, the field work developed at the archaeological site during this specific year (2008).In the mark of the analytical work a significant number of ceramic individuals (144) from the different stratigraphical units from various areas of the excavation of Termez and Tchinguiz Tepe sampled duringthe new and previous field works has been archaeometrically characterized. This specific material includedindividuals dated into the Hellenistic and Sassanian period, which has been confirmed by C14dating upon organic samples.At the same time, in the mark of the field work of 2008 the archaeological record, already started tobe under study during the excavation of 2007, has been completed and two new archaeological recordshave been registered on of which is located in the area of Tchinguiz Tepe. For the archeological studythe information of the previous geophysical prospecting has been indisputably taken into considerationand the same methodology has been applied to crosscheck the latter archaeological results.

Preliminary Report of the work of the International Pluridisciplinary Archaeological Expedition to Bactria (2009)

Institute of Archaeology & Institute of Fine Arts. Academy of Science of the Republic of Uzbekistan- Universitat de Barcelona- Ministerio de Cultura (Gobierno de España)- Ministerio de Ciencia e Innovación (Gobierno de España)

Science in Western Islam. The circulation of knowledge in Mediterranean region

La Mediterrània ha estat gresol de la circulació d¿idees i persones des de fa mil·lennis. Durant l¿edat mitjana, però, el moviment més rellevant va ser, tal vegada, el que es va produirentre l¿Orient (Maixriq) i l¿Occident (Magrib) islàmics. Els viatges d¿estudis, íntimament units a les prescripcions religioses,varen convertir els científics musulmans en membres especialment actius en la difusió dels coneixements i dels avenços ques¿anaven adquirint a la capital de l¿imperi, Bagdad. Lluny de ser mers «transportistes» de la ciència, el nivell cultural assolit durantl'edat d'or abbassí els va convertir en un dels clímaxs intel·lectuals de la història. Al principi, tot i restar en un discret segonpla, els científics del nord d¿Àfrica i, especialment, els científicsd'al-Andalus varen tenir un paper essencial en la transmissióde la ciència oriental cap a una Europa que en va recollir el testimoni.Per això l¿aportació de la cultura araboislàmica és un esglaó sense el qual és impossible entendre la ciència posterior.Els camps conreats foren diversos: medicina, agronomia,òptica... però l¿àmbit que presidí la ciència fou, sens dubte,l¿astronomia (relacionada, al seu torn, amb les matemàtiques i la geografia). Els noms dels astrònoms més rellevants (desd¿al-Khwarizmi fins a Azarquiel) i les fites que varen assolir justifiquen que fossin coneguts per un públic ampli. Malgrat tot, continuen essent uns grans desconeguts.