Higher Fluctuating Asymmetry: Indication of Stress on Anadara trapezia Associated with Contaminated Seagrass

Seagrasses are marine angiosperms that colonize near-shore environments. Concern\ud has arisen over increasing concentrations of heavy metals in these systems resulting\ud from industrial and urban development due to the ability of seagrass to accumulate\ud trace metals from the environment without showing any impact on their productivity.\ud This may pose a threat to a coastal community because the polluted seagrass will then\ud provide a source of contamination to seagrass consumers. The main aim of this study\ud was to determine whether there was any detectable effect of heavy metal pollution in\ud seagrass on associated fauna. Fluctuating asymmetry of shell structure of a bivalve,\ud Anadara trapezia, were employed as biomarkers for this environmental study. The\ud result from this study revealed that A. trapezia showed distinct morphological characters\ud and high shell asymmetry in the polluted location. Thus, A. trapezia associated\ud with seagrass may be responsive to heavy metal stress and possibly a good indicator of\ud heavy metal pollution in this system. The present study discusses the possibility of\ud using a more cost-effective biomarker to define areas of heavy metal pollution

Dimensiones en planta de una protección de estribo y erosiones resultantes

Las protecciones flexibles son un recurso ingenieril ampliamente utilizado para contrarrestar los procesos erosivos locales que se desarrollan en torno a los estribos de puentes. En la literatura especializada se ha puesto énfasis en determinar el espesor adecuado de los elementos que constituyen el revestimiento. Sin embargo, son limitados los estudios que refieren a las dimensiones en planta mínimas requeridas y su influencia sobre las máximas profundidades de erosión. En este trabajo se analiza de manera experimental la incidencia que la extensión de una protección flexible colocada junto a un estribo de un puente aliviador tiene tanto sobre las máximas profundidades de erosión resultantes como sobre la geometría de las hoyas de socavación desarrolladas. La experimentación fue realizada en un canal de grandes dimensiones, capaz de representar de forma adecuada las particulares condiciones del flujo en las inmediaciones de un puente aliviador. Se ensayaron diferentes tamaños de protección flexible y anchos del escurrimiento en la sección del puente, manteniendo constante la geometría del estribo y las condiciones hidráulicas, estas últimas evaluadas en término del tirante y velocidad media del flujo junto al estribo. Los resultados obtenidos demostraron que las máximas profundidades de erosión son independientes del ancho de la protección, pero la posición de las mismas y la geometría que adquiere la hoya de erosión están fuertemente gobernadas por esas características del revestimiento. Asimismo, se ha comprobado que los volúmenes removidos se encuentran muy influenciados por la proporción de sección de paso del puente que está protegida

Translational Fluctuating Asymmetry and Leaf Dimension in Seagrass, Zostera capricorni Aschers in a Gradient of Heavy Metals

Methodology for measuring translational fluctuating asymmetry (TFA) on leaves of\ud seagrass, Zostera capricorni Aschers has been developed and tested to detect a subtle\ud effect of environmental stress associated with heavy metal pollution on developmental\ud instability. Our analyses showed that concentration of heavy metals (Cd, Pb, Cu, Zn,\ud Se) in leaves and roots of the seagrass were significantly higher in the polluted location\ud than in relatively unpolluted locations. We found significant differences in TFA\ud between different locations, showing that the method is sensitive enough to detect spatial\ud differences even within a rather small water body, but these differences were not\ud associated with a higher concentration of heavy metals, i.e. plants from the polluted\ud location did not show higher TFA. Possibly, seagrass can store heavy metals in their\ud tissues and protect their development from the toxic effect, or the effect of heavy metals\ud in the natural environment is confounded by other environmental factors. At the same\ud time, we found that plants from the polluted location had narrower leaves than in relatively\ud unpolluted ones, which may be caused by heavy metals or associated factors

Heavy metal impact on growth and leaf asymmetry of seagrass, Halophila ovalis

Heavy metal impact on seagrass.A major threat to the seagrass ecosystem worldwide, due to the growth of human population along the coastal environment, is pollution or contamination resulting from industrial and urban development. Although seagrass appears to be rather resistant to heavy metal contaminants, these substances may possibly harm some components of the seagrass and such responses have not been examined to a significant extent. Lead (Pb) and copper (Cu) was tested on seagrass, Halophila ovalis, to see whether the metals are environmental sressor on the seagrass. Reduced growth rate of the seagrass was observed both in Pb and Cu treatments.Leaf size of the plant also reduced as the metal concentrations increased and when the plants were exposed to the heavy metal for longer duration. As increased leaf asymmetry was more apparent at the 2 mg/L Cu treatment and no significant increases in fluctuating asymmetry were found in Pb treatment or in low levels of Cu treatment. Further discussion were made in view of selecting non-costly bioindicators of heavy metal contamination

Whole Brain Size and General Mental Ability: A Review

We review the literature on the relation between whole brain size and general mental ability (GMA) both within and between species. Among humans, in 28 samples using brain imaging techniques, the mean brain size/GMA correlation is 0.40 (N = 1,389; p < 10−10); in 59 samples using external head size measures it is 0.20 (N = 63,405; p < 10−10). In 6 samples using the method of correlated vectors to distill g, the general factor of mental ability, the mean r is 0.63. We also describe the brain size/GMA correlations with age, socioeconomic position, sex, and ancestral population groups, which also provide information about brain–behavior relationships. Finally, we examine brain size and mental ability from an evolutionary and behavior genetic perspective

Contrasting styles of (U)HP rock exhumation along the Cenozoic Adria-Europe plate boundary (Western Alps, Calabria, Corsica)

Since the first discovery of ultrahigh pressure (UHP) rocks 30 years ago in the Western Alps, the mechanisms for exhumation of (U)HP terranes worldwide are still debated. In the western Mediterranean, the presently accepted model of synconvergent exhumation (e.g., the channel-flow model) is in conflict with parts of the geologic record. We synthesize regional geologic data and present alternative exhumation mechanisms that consider the role of divergence within subduction zones. These mechanisms, i.e., (i) the motion of the upper plate away from the trench and (ii) the rollback of the lower plate, are discussed in detail with particular reference to the Cenozoic Adria-Europe plate boundary, and along three different transects (Western Alps, Calabria-Sardinia, and Corsica-Northern Apennines). In the Western Alps, (U)HP rocks were exhumed from the greatest depth at the rear of the accretionary wedge during motion of the upper plate away from the trench. Exhumation was extremely fast, and associated with very low geothermal gradients. In Calabria, HP rocks were exhumed from shallower depths and at lower rates during rollback of the Adriatic plate, with repeated exhumation pulses progressively younging toward the foreland. Both mechanisms were active to create boundary divergence along the Corsica-Northern Apennines transect, where European southeastward subduction was progressively replaced along strike by Adriatic northwestward subduction. The tectonic scenario depicted for the Western Alps trench during Eocene exhumation of (U)HP rocks correlates well with present-day eastern Papua New Guinea, which is presented as a modern analog of the Paleogene Adria-Europe plate boundary