Absorption and adsorption of hydrogen in B2-FeA1: Ab initio study

International audienceUsing the density functional theory and the pseudo-potential approach, the behavior of atomic hydrogen in bulk and surface of B2-FeAl was studied. In Al-rich environment without structural defects, the hydrogen atom prefers to stabilize in octahedral site. However, the most favorable double defect cases were hydrogen with Al-vacancy followed by hydrogen with Al-antisite. For the surface case, the obtained results have shown that H was always attracted by (0 0 1) and (1 1 0) surfaces. The diffusion of H to the bulk was predicted to be favorable for (1 1 0) and unfavorable for (0 0 1) Fe-terminated. The behavior of H in B2-FeAl H was highly dependent on the local environment and the surface orientation

Distribution of cold-water corals in the Whittard Canyon, NE Atlantic Ocean

The deep-sea floor occupies about 60% of the surface of the planet and is covered mainly by fine sediments. Most studies of deep-sea benthic fauna therefore have concentrated on soft sediments with little sampling of hard substrata, such as rocky outcrops in submarine canyons. Here we assess the distribution and abundance of cold-water corals within the Whittard Canyon (NE Atlantic) using video footage from the ROV Isis. Abundances per 100 m of video transect were calculated and mapped using ArcGIS. The data were separated into five substratum types, ‘Sediment’, ‘Mixed Sediment and Rock’, ‘Sediment Slope’, ‘Lophelia reef’ and ‘Lophelia and rock’. Abundance and community structure were compared. A maximum abundance of 855 coral colonies per 100 m of ROV transect were observed with 31 coral types identified. Highest taxon richness was observed along a ‘Lophelia reef’ area, although a larger richness of Octocorallia was observed away from the ‘Lophelia reef’ areas. ‘Lophelia reef’ and ‘Lophelia and rock’ areas were found to have a different coral community structure from the other substratum types. We suggest this is the result of Lophelia outcompeting other coral types because there is increased coral taxon richness in areas without Lophelia. We also hypothesise that the hydrodynamic regime within the Whittard Canyon results in differences in organic matter input including higher quality food, in comparison with other deep-water environments, leading to changes in the coral communities

Antioxidant Response in Duckweed After Exposure to Secondary Effluent from Municipal Wastewater Treatment Plant, Elazığ,Turkey

The aim of this study is to evaluate the effects of the effluent of Elazig Municipality Wastewater Treatment Plant on the oxidative defense capacity of aquatic plants (Lemna minor L. and Lemna gibba L.). For this purpose, malondialdehyde (MDA), glutathione (GSH), oxidized glutathione (GSSG), vitamin A (retinol), vitamin E (α-tocopherol), and vitamin C (Ascorbic acid) levels were determined by the HPLC (high performance liquid chromatography) in the control groups and the groups adapting to reactors fed with discharge water. The depletion of vitamins (A, E, and C), decrease of GSH/GSSG ratio, and increase of MDA that reflect a precarious state of the cell in L. minor L. and L. gibba L. were observed after exposure to wastewater. It can be suggested that the selected biomarkers are useful in understanding the biochemical mechanisms of the secondary effluents from wastewater treatment plant in L. minor L. and L. gibba L. as early warning indicators