Heavy metals contamination of the Quaternary coral reefs, Red Sea coast, Egypt

In order to assess pollutants and impact of environmental changes along the Egyptian Red Sea coast, seven recent and Pleistocene coral species have been analyzed for Zn, Pb, Mn, Fe, Cr, Co, Ni, and Cu. Results show that the concentration of trace elements in recent coral skeletons is higher than those of Pleistocene counterpart except for Mn and Ni. In comparison with recent worldwide reefs, the present values are less than those of Central America coast (iron), Gulf of Aqaba, Jordan (lead, copper), Gulf of Mannar, India (chromium, zinc, manganese), Costa Rica, Panama (chromium, nickel), North-west coast of Venezuela and Saudi Arabia (copper). The present values are higher than those of Gulf of Aqaba, Jordan (iron, zinc, manganese), Gulf of Mannar, India (lead, cobalt, nickel), North-west coast of Venezuela (lead, zinc, chromium, manganese), Australia (copper, nickel, zinc, manganese). The highest values were recorded in Stylophora pistillata (iron, lead and copper), Acropora cytherea (cobalt), Pocillopora verrucosa (zinc) and the lowest concentrations were recorded in Goniastrea pectinata (iron, chromium, copper and nickel), Favites pentagona (lead, zinc and manganese), and Porites lutea (cobalt). The differences in metals content among the studied species are attributed to differences in microstructure and microarchitecture.     

Spatiotemporal drought variability in northwestern Africa over the last nine centuries

Changes in precipitation patterns and the frequency and duration of drought are likely to be the feature of anthropogenic climate change that will have the most direct and most immediate consequences for human populations. The latest generation of state-of-the-art climate models project future widespread drying in the subtropics. Here, we reconstruct spatially-complete gridded Palmer drought severity index values back to A.D. 1179 over Morocco, Algeria, and Tunisia. The reconstructions provide long-term context for northwest African hydroclimatology, revealing large-scale regional droughts prior to the sixteenth century, as well as more heterogeneous patterns in sixteenth, eighteenth, and twentieth century. Over the most recent decades a shift toward dry conditions over the region is observed, which is consistent with general circulation model projections of greenhouse gas forced enhanced regional subtropical drought.     

Induction of tributyltin-binding protein type 2 in Japanese flounder, Paralichthys olivaceus, by exposure to tributyltin-d27

In this study, individual Japanese flounder were intraperitoneally injected with 2 μg tributyltin-d27 (TBT-d27) fish⁻¹. Blood samples were collected on day 7 after injection. TBT-binding protein types 1 and 2 (TBT-bp1, -bp2) in the blood serum were quantified by western blotting analysis. As a result, the concentration of TBT-bp2 in TBT-d27 treated group increased to 220% of that in the solvent control, whereas the TBT-bp1 concentration decreased to 65% of that in the solvent control. Additionally, a positive relationship between the concentrations of TBT-bp2 and TBT was observed in blood sera of wild and cultured flounder. We suggest that TBT-bp2 is produced in response to TBT exposure and may play an important role in fish physiology.     

Contemporary 14C radiocarbon levels of oxygenated polybrominated diphenyl ethers (O-PBDEs) isolated in sponge-cyanobacteria associations

Considerable debate surrounds the sources of oxygenated polybrominated diphenyl ethers (O-PBDEs) in wildlife as to whether they are naturally produced or result from anthropogenic industrial activities. Natural radiocarbon (¹⁴C) abundance has proven to be a powerful tool to address this problem as recently biosynthesized compounds contain contemporary (i.e. modern) amounts of atmospheric radiocarbon; whereas industrial chemicals, mostly produced from fossil fuels, contain no detectable ¹⁴C. However, few compounds isolated from organisms have been analyzed for their radiocarbon content. To provide a baseline, we analyzed the ¹⁴C content of four O-PBDEs. These compounds, 6-OH-BDE47, 2′-OH-BDE68, 2′,6-diOH-BDE159, and a recently identified compound, 2′-MeO-6-OH-BDE120, were isolated from the tropical marine sponges Dysidea granulosa and Lendenfeldia dendyi. The modern radiocarbon content of their chemical structures (i.e. diphenyl ethers, C₁₂H₂₂O) indicates that they are naturally produced. This adds to a growing baseline on, at least, the sources of these unusual compounds.     

Spatio-temporal evolution of Yellowstone deformation between 1992 and 2009 from InSAR and GPS observations

In this study, the spatio-temporal evolution of Yellowstone deformation between 1992 and 2009 is monitored using interferometric synthetic aperture radar (InSAR) data acquired by the European Remote-Sensing Satellites (ERS-1 and ERS-2) and the Environmental Satellite (ENVISAT). These data are combined with continuous global positioning system (GPS) measurements to identify four discrete episodes of caldera subsidence and uplift, these episodes are: 1992–1995 (subsidence of 2.7 cm/year), 1996–2000 (subsidence of 0.5 cm/year, with local uplift of 1.7 cm/year at Norris), 2000–2004 (subsidence of 0.7 cm/year, with local uplift of 0.6 cm/year at Norris), and 2004–2009 (uplift of 3–8 cm/year, with local subsidence of 1–4 cm/year at Norris). We construct the full three-dimensional velocity field of Yellowstone deformation for 2005–2006 from ascending and descending ENVISAT orbits. The InSAR three-dimensional velocity field and three-component GPS measurements indicate that the majority of the observed deformation (3–8 cm/year) across the Yellowstone caldera and near Norris Geyser Basin (NGB) occurred in the vertical direction between the summers of 2005 and 2006. During this time, significant lateral displacements of 3–7 cm/year also occurred in the east–west direction at the southeastern and western rims of the Yellowstone caldera and in the area between Hebgen Lake and NGB. Minor north–south displacements of about 0.2 cm/year also occurred, however, in the southwestern section of the caldera and near Yellowstone Lake during the same period. The calculated three-dimensional velocity field for 2005–2006 implies the existence of two pressure-point sources, beneath the two structural resurgent domes in the Yellowstone caldera, connected by a planar conduit, rather than a single, large sill as proposed in previous studies. Furthermore, no measurable displacements occurred along any fault zone across the caldera during the entire period of observation (1992–2009). Therefore, we infer that magmatic and hydrothermal processes beneath the Yellowstone caldera and NGB were the main sources of deformation.     

Gravity and magnetotelluric investigations to elicit the origin of Hammam Faraun hot spring,Sinai Peninsula,Egypt

There is a clear correlation between the principal areas of current geothermal development and the seismically active boundaries of the moving segments of lithosphere defined by the plate tectonic models of the Earth. The tectonic position of Egypt in the northeastern corner of African continent suggests that the most important areas for geothermal exploration are in the region where a cluster of hot springs with varied temperatures was located around the Gulf of Suez. Gravity and magnetotelluric surveys were made in the area of Hammam Faraun hot spring, which represents the most promising area for geothermal development in Egypt. These surveys were carried out for the purpose of eliciting the origin of Hammam Faraun hot spring. The results of the analyses and interpretations of these data show that the heat source of the hot spring is due to uplift of hot basement rock. This uplift may cause deep circulation and heating of the undergroundwater.     

Characterization and Application of Dried Plants to Remove Heavy Metals,Nitrate, and Phosphate Ions from Industrial Wastewaters

Low cost adsorbents were prepared from dried plants for the removal of heavy metals, nitrate, and phosphate ions from industrial wastewaters. The efficiency of these adsorbents was investigated using batch adsorption technique at room temperature. The dried plant particles were characterized by N₂ at 77 K adsorption, scanning electron microscopy, energy dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy, and phytochemical screening. The adsorption experiments showed that the microparticles of the dried plants presented a good adsorption of heavy metals, phosphate, and nitrate ions from real wastewaters. This adsorption increased with increasing contact time. The equilibrium time was found to be 30 min for heavy metals and nitrate ions and 240 min for phosphate ions. After the adsorption process, the Pb(II) concentrations, as well as those of Cd(II), Cu(II), and Zn(II) were below the European drinking water norms concentrations. The percentage removal of heavy metals, nitrates, and phosphates from industrial wastewaters by dried plants was ～94% for Cd²⁺, ～92% for Cu²⁺, ～99% for Pb²⁺, ～97% for Zn²⁺, ～100% for ${\rm NO}_{{\rm 3}}^{{-} } $ and ～77% for ${\rm PO}_{{\rm 4}}^{3{-} } $ ions. It is proved that dried plants can be one alternative source for low cost absorbents to remove heavy metals, nitrate, and phosphate ions from municipal and industrial wastewaters.     

Is there a hidden near surface salt diapir in the Guelma Basin,north-east of Algeria?

The diapiric province of north-eastern Algeria and Tunisia extends NE–SW over several hundreds of kilometres. Available, geophysical and geological investigations were focused on the study of known diapiric outcrop. In contrast to the existing work, our study is focused on to identify a new hidden near surface salt diapir in the Guelma Basin, north-east of Algeria.Integrated geophysical study comprising aeromagnetic, gravimetric and DC resistivity data calibrated with existing well information provides new insights into the geometry of the geologic structure of Guelma Basin. Spatial correlation between magnetic low, strong gravity minimum and resistivity high reveal a hidden near surface salt diapir. The Guelma salt diapir is topped by a local topographic high which follows exactly the underlying salt body. Joint gravity-magnetic modelling indicates that salt is deeply rooted and has a dome-like shape. The Guelma salt diapir was triggered by normal faulting and is directly controlled by regional extension.     

Land use change and resource management in the Jnane Mas valley (Khenifra,Middle Atlas,Morocco)

The purpose of this paper is to bring into light the landscape change and natural resources management in the Moroccan Middle Atlas across centuries. The pastoral way of life prevailed for many centuries. However, following the results of this research, evidence of important socioeconomic changes and resources use is found. Ancient agricultural activities, as well as the exploitation of the forest and even mineral resources have been growing activities over time. The survey shows that the agricultural activity has existed for several centuries as indicated by terraces and encrusted travertine channels used for irrigation. The landscapes and the ways of resources use are therefore in continuous change. The increasing needs in water and agriculture for demographic and climatic reasons (the dry periods in summer or periodic droughts) generated because of intensive over-exploitation of resources. The vegetation degraded facing human pressure (the pastoral activities, the coal of wood making, the lime manufacturing, etc.). Field observations show that irrigation has been used in this domain, for several centuries. Travertine channels, encrusted in the valleys of Jnane Mas and Arougou, illustrate these ancient uses of water resources for agriculture irrigation.     

Polybrominated diphenyl ethers and their methoxylated analogs in mullet (Mugil cephalus) and sea bass (Dicentrarchus labrax) from Bizerte Lagoon, Tunisia

Concentrations of ten polybrominated diphenyl ethers (PBDEs) and eight methoxylated polybrominated diphenyl ethers (MeO-PBDEs) in mullet (Mugil cephalus) and sea bass (Dicentrarchus labrax) collected from the Bizerte Lagoon and the Mediterranean Sea were investigated. To the best of our knowledge, this is the first report of these compounds in marine fishes from Tunisia. The PBDE mean concentrations in fish from Bizerte Lagoon were 45.3 and 96.2 ng g(-1) lw respectively in mullet and sea bass, while the concentrations of these compounds in mullet and sea bass from Mediterranean Sea were 7.80 and 27.9 ng g(-1) lw respectively. MeO-PBDE concentrations in mullet and sea bass from Bizerte Lagoon ranged from 6.46 to 286 ng g(-1) lw and from 49.4 to 798 ng g(-1) lw respectively, while the concentrations of these compounds in mullet and sea bass from Mediterranean Sea ranged from 190 to 401 ng g(-1) lw and from 353 to 578 ng g(-1) lw respectively. The total PBDEs and total MeO-PBDEs concentration in fish from Bizerte Lagoon were similar or slightly lower than those reported for other species from other locations around the world.