Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

En els darrers anys la crítica historiogràfica envers la representació dels mossàrabs com a factors de continuïtat identitària, religiosa i lingüística ha estat objecte d’un canvi important. L’atenció ja no es dirigeix tant a la capacitat de pervivència de les estructures eclesiàstiques i les comunitats locals, com a l’abast de l’arabització i la pèrdua dels referents culturals llatins. La rapidesa i la intensitat de l’assimilació lingüística dels cristians d’al-Andalus són tan notables que permeten plantejar la qüestió de la convergència de les seues formes d’organització social amb les dels musulmans i, per tant, el distanciament respecte a aquelles pròpies dels cristians del nord. El fet que l’expansió dels regnes cristians s’efectués en un ambient eclesiàstic de recel i pressió ideològica gens favorable a la conservació de les formes de cristianisme estranyes a l’ortodòxia llatina atorgaria als mossàrabs incorporats una alteritat essencial que els menaria a la marginació i l’extinció social.

Metal pollution and distribution in marine surface (0-5 cm) sediments of the Baja California border region were characterized during 1989. The total organic carbon, clay, silt and sand contents in the sediments and their correlation with the metals examined were also analysed. The results show higher concentrations (µg g–1 dry weight) of Al (7493), Mn (78.8) Cr (24.2) Zn (16.5) Cu (6.2) Cd (0.29) and Ag (0.30) in sediments of the 60-m isobath, with a gradient in their concentrations toward the shoreline. Analyses of simple correlation, principal components and similarity indicate that this behaviour is explained by the association of the elements with grain size and with silicoaluminate and organic matter contents. The possible influence of pollution and productivity phenomena as other processes that may control the distribution and origin of the metals in the study area, particularly Cd and Ag, is also noted. The results obtained show a decrease in Zn (15%), Cu (16%) Ag (20%) and Cd (22%) with respect to the values measured in coastal sediments of San Diego, California, in 1979.

The sediments of Chelem Lagoon, on the coast of the Gulf of Mexico, north of the Yucatán Peninsula, were studied measuring the nutrient concentrations in the interstitial water. The average values were: ammonium 459 ± 281 µM, peaking up to 1,045 µM; nitrite 1.8 ± 1.8 PM, with a maximum of 5.3 µM; nitrate 8.2 ± 10.3 µM, reaching 34.7 µM, phosphate 0.4 ± 0.4 µM, with a maximum of 1.1 µM. Fluxes were estimated with Fick’s first law equation. In al1 cases, the mean flux of the 14 samples from the lagoon were from the sediment to the water column; these values were 182 µmol/m2h for ammonium, 0.5 µmol/m2h for nitrite, 1.9 µmol/m2h for nitrate and 0.03 µmol/m2h for phosphate. In order to determine denitrification rates, incubations of the sediments were carried out under anaerobic conditions with water from the lagoon enriched with nitrate; denitrification was found to be active in five of the 14 samples, with the highest rate in sample No. 8 (16.07 µmol/m2h), which had the greatest content of organic matter (9.2%) and the highest nitrate flux (from the water to the sediment). The calculation of the net flux in the Chelem area showed an important supply from the sediment to the water column of the four nutrients studied, greatest in ammonium.