Effect on benthic communities of a major input of organic matter and other pollutants (coast off Barcelona,Western Mediterranean)

Benthic communities on soft bottoms off Barcelona, at and around two main pollution sources, the mouth of the Besòs River and the outlet of the submarine pipeline draining wastewater and organic sludges from the wastewater treatment plant of Sant Adrià del Besòs, have been studied. Samples were obtained with a Van Veen grab from 36 stations covering a 100 km² grid, between 10 and 70 m in depth. The effect of both pollution sources is clearly seen both at the species (the following macrofauna groups have been studied: Polychaeta, Mollusca, Echinodermata and Crustacea Decapoda) and community levels. The distribution of species and individuals numbers, species diversity and a pollution index, and of some selected (indicator) polychaeta species, all clearly define the degree of environmental degradation and the extent of the areas under the influence of the organic pollution.     

Characterization of black crusts developed on historic stones with diverse mineralogy under different air quality environments

Environmental Science and Pollution Research - Black crusts (BCs) are one of the most critical alteration forms found on stones belonging to architectural heritage. Since they could be considered...     

Effectiveness evaluation of glyphosate oxidation employing the H2O2/UVC process: Toxicity assays with Vibrio fischeri and Rhinella arenarum tadpoles

The H₂O₂/UVC process was applied to the photodegradation of a commercial formulation of glyphosate in water. Two organisms (Vibrio fischeri bacteria and Rhinella arenarum tadpoles) were used to investigate the toxicity of glyphosate in samples M_1, M₂, and M₃ following different photodegradation reaction times (120, 240 and 360 min, respectively) that had differing amounts of residual H₂O₂. Subsamples of M₁, M₂, and M₃ were then used to create samples M_1,E, M_2,E and M_3,E in which the H₂O₂ had been removed. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities were measured in tadpoles to determine possible sub-lethal effects. In V. fischeri, M_1,E, which was collected early in the photodegradation process, caused 52% inhibition, while M_3,E, which was collected at the end of the photodegradation process, caused only 17% inhibition. Survival of tadpoles was 100% in samples M₂, M₃, and in M_1,E, M_2,E and M_3,E. The lowest percentages of enzymatic inhibition were observed in samples without removal of H₂O₂: 13.96% (AChE) and 16% (BChE) for M₂, and 24.12% (AChE) and 13.83% (BChE) for M₃. These results show the efficiency of the H₂O₂/UVC process in reducing the toxicity of water or wastewater polluted by commercial formulations of glyphosate. According to the ecotoxicity assays, the conditions corresponding to M₂ (11 ± 1 mg a.e. L^?1 glyphosate and 11 ± 1 mg L^?1 H₂O₂) could be used as a final point for glyphosate treatment with the H₂O₂/UV process.     

Distribution of a population of annelid polychaetes in the “trottoir” of the midlittoral zone on the coast of North-East Spain,Western Mediterranean

The discharge and mode of action of the microbasic mastigophores (b-Rhabdoids) of Anemonia sulcata Pennant (Anthozoa) tentacles were examined using light and electron microscopical techniques. The statistical analysis of different morphological parameters of 100 nematocysts before and after their complete discharge revealed four different phases in the process of discharge. The first phase consists of the opening of the three opercular flaps. The second phase is characterized by the extrusion of the shaft. Osmotic pressure generated by the nematocyst propagates the extremely fast shaft discharge. The third phase, the evagination of the long tubule, is propagated by intrinsic mechanical forces stored in the tubule's twists and coils. During the process of evagination the tubule length increases by 95%, its circumference by 17%. Its forward motion is produced by the dilatation of its circumference and undoing of its twists. This motion is supported by the pressure which is generated by the hydration of the capsular matrix. The fourth phase consists in the extrusion of soluble capsular material at the tip of the evaginated tubule. During discharge the net volume of the nematocyst increases by 182%. This expansion is only possible if a high osmotic pressure is generated within the cyst. The extrusion of the shaft is the crucial phase in the discharge of the microbasic mastigophores, because without the puncture produced by the shaft the tubule is not able to overcome even surfaces of low viscosity media. The function of these tentacular nematocysts is the mechanical capture of prey organisms and, most probably, the introduction of unknown toxins into the latter.