The Banhad?o Alkaline Complex, Southeastern Brazil: source and evolution of potassic SiO2-undersaturated high-Ca and low-Ca magmatic series

The Cretaceous Banhad?o alkaline complex in southeastern Brazil presents two potassic SiO₂-undersaturated series. The high-Ca magmatic series consist of initially fractionated olivine (Fo_92-91) + diopside (Wo_48-43En_49-35Ae_0-7), as evidenced by the presence of xenocrysts and xenoliths. In that sequence, diopside (Wo_47-38En_46-37Ae_0-8) + phlogopite + apatite + perovskite (Prv_>92) crystallized to form the phlogopite melteigite and led to the Ca enrichment of the magma. Diopside (Wo_47-41En_32-24 Ae_3-14) continued to crystallize as an early mafic mineral, followed by nepheline (Ne_74.8-70.1Ks_26.3-21.2Qz_7.6-0.9) and leucite (Lc_65-56) and subsequently by melanite and potassic feldspar (Or_85-99Ab_1-7) to form melanite ijolites, wollastonite-melanite urtites and melanite-nepheline syenites. Melanite-pseudoleucite-nepheline syenites are interpreted to be a leucite accumulation. Melanite nephelinite dykes are believed to represent some of the magmatic differentiation steps. The low-Ca magmatic series is representative of a typical fractionation of aegirine-augite (Wo_36-29En_25-4Ae_39-18) + alkali feldspar (Or_57-96Ab_3-43) + nepheline (Ne_76.5-69.0Ks_19.9-14.4Qz_15.1-7.7) + titanite from phonolite magma. The evolution of this series from potassic nepheline syenites to sodic sodalite syenites and sodalitolites is attributed to an extensive fractionation of potassic feldspar, which led to an increase of the NaCl activity in the melt during the final stages forming sodalite-rich rocks. Phonolite dykes followed a similar evolutionary process and also registered some crustal assimilation. The mesocratic nepheline syenites showed interactions with phlogopite melteigites, such as compatible trace element enrichments and the presence of diopside xenocrysts, which were interpreted to be due to a mixing/mingling process of phonolite and nephelinite magmas. The geochemical data show higher TiO₂ and P₂O₅ contents and lower SiO₂ contents for the high-Ca series and different LILE evolution trends and REE chondrite-normalized patterns as compared to the low-Ca series. The ⁸⁷Sr/⁸⁶Sr, ¹⁴³Nd/¹⁴⁴Nd, ²⁰⁶Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb initial ratios for the high-Ca series (0.70407–0.70526, 0.51242–0.51251, 17.782–19.266 and 38.051–39.521, respectively) were slightly different from those of the low-Ca series (0.70542–0.70583, 0.51232–0.51240, 17.758–17.772 and 38.021–38.061, respectively). For both series, a CO₂-rich potassic metasomatized lithospheric mantle enriched the source with rutile-bearing phlogopite clinopyroxenite veins. Kamafugite-like parental magma is attributed to the high-Ca series with major contributions from the melting of the veins. Potassic nephelinite-like parental magma is assigned to the low-Ca series, where the metasomatized wall-rock played a more significant role in the melting process.     

Probabilistic risk assessment of common booster biocides in surface waters of the harbours of Gran Canaria (Spain)

The presence of booster biocides in the aquatic environment has been associated with a risk to non-target species due to their proven toxicity. The aim of the present study was to determine the spatial and temporal distribution of common booster biocides in different harbours of the island of Gran Canaria (Spain) and evaluate, by means of a probabilistic risk assessment (PRA), the ecological risk posed by these compounds. With these objectives, a monitoring campaign was conducted between January 2008 and May 2009, collecting a total of 182 seawater samples. Four common booster biocides (TCMTB, diuron, Irgarol 1051 and dichlofluanid) were monitored. Diuron levels ranged between 2.3 and 203 ng/L and Irgarol 1051 between 2.4 and 146.5 ng/L. The ecological risk associated with these levels was always low, however, with probabilities of exceeding the 10th percentile of autotroph toxicity below 3.5%.     

Degradation and Detoxification of Chlorophenols in Continuous‐Flow Fixed‐Bed Aerobic Reactors

An indigenous bacterial strain of Delftia sp. capable of degrading 2,4‐dicholorophenol and an indigenous bacterial community that degrades 2,4,6‐trichlorophenol (TCP) were employed to inoculate continuous down‐flow fixed‐bed reactors. Continuous‐reactors were constructed from PVC employing hollow PVC cylinders as support material. Synthetic wastewater was prepared by dissolving the corresponding chlorophenol in non‐sterile groundwater. Biodegradation was evaluated by spectrophotometry, chloride release, GC, and microbial growth. Detoxification was evaluated by using Daphnia magna as test organism. Delftia sp. was able to remove an average of 95.6% of DCP. Efficiency in terms of chemical oxygen demand (COD) was of 88.9%. The indigenous bacterial community that degrades TCP reached an average efficiency of 96.5 and 91.6% in terms of compound and COD removal, respectively. In both cases stoichiometric removal of chloride and detoxification was achieved. When synthetic wastewater feed was cut off for 7 days, both reactors showed a fast recovery after inflow restarting, reaching average outlet concentration values within 36 h. The promising behavior of the microorganisms and the low cost of the reactors tested allow us to suggest their possible application to remediation processes.     

SLA–chlorophyll-a variability and covariability in the Algero-Provençal Basin (1997–2007) through combined use of EOF and wavelet analysis of satellite data

Data reduction and signal decomposition techniques have been applied to a large bio-physical remotely sensed dataset covering the decade 1997–2007. The aim was the estimation of the spatial (basin and sub-basin scales) and temporal (seasonal and interannual) variability of sea level anomalies and chlorophyll-a concentration in the Algero-Provençal Basin, as well as the study of their covariability. Empirical orthogonal functions, wavelet analysis, singular value decomposition and correlation maps have been successfully used to individuate the patterns of (co)variability of the investigated fields. The seasonal variability of the phytoplanktonic biomass is divided in two distinct modes, timewise and spacewise separated. Positive interannual events are related to anomalies in 1999 and 2005, while the main (negative) anomaly is that of summer 2003, associated to the European 2003 heatwave. The analysis of the sea level anomalies shows a minimum in the formation of anticyclonic Algerian eddies during that period. The largest anticorrelation between sea level anomalies and phytoplanktonic biomass is found in the central zone of the basin, suggesting a clear biological response to the shoaling/deepening of the isopycnae and so to the nutrient injection into the euphotic layer. The analysis suggests that the driver of the variability of the nutricline depth in this central area is the displacement (seasonal) of the North Balearic Front and the formation/action of the frontal eddies.     

Polymorphism of As4S3 (tris-(μ2-sulfido)-tetra-arsenic): accurate structure refinement on natural α- and β-dimorphites and inferred room temperature thermodynamic properties

An accurate structure refinement, using single-crystal X-ray diffraction data, on natural α- and β-dimorphites collected at Solfatara di Pozzuoli, in the Phlegraean Fields, near Naples and at Vesuvius (Italy) is reported. Theoretical calculations at various levels of sophistication have been used to calculate molecular vibrational frequencies and gas-phase specific heats, to analyze the crystal packing, and to estimate lattice energies of both phases. All computational methods contribute to demonstrate that the β-phase is the thermodynamically stable one at room temperature.     

Recovery of the macrozoobenthic community after severe dystrophic crises in a Mediterranean coastal Lagoon (Orbetello, Italy)

The Orbetello lagoon, one of the largest Western Mediterranean lagoons, was affected by high algal blooms and severe anoxic crises in 1992 and 1993, with fish mortality throughout most of the lagoon and a drastic reduction of benthic species. Many measures were undertaken between 1994 and 1996 to remove the severe eutrophication of this lagoon. Such measures included harvesting of the floating seaweed biomass, removal of all wastewater and sea channel enlargement by dredging activity. The aim of the present research was to study the macrozoobenthic assemblage in 1999 and to compare it with previous research in order to assess the recovery of the lagoon. A total of 106 taxa and 45,175 individuals were collected in three areas (sea inlets, western and eastern lagoon) having different organic matter loading during winter and summer. The results of multivariate and correlation analyses indicated that trophic status and its seasonal dynamics were crucial in determining species distribution among the different areas. Moreover, comparison of the macrozoobenthic structure between winter 1995 and 1999 showed differences in species composition and structural parameters in the western and eastern lagoon, where a clear recovery of benthic assemblages was observed in 1999. However, the dominance of opportunistic species in most of the lagoon and the decrease in some structural parameters during summer suggested that this basin still presented signs of disturbance in 1999, six years after the last extended anoxic crises and even after completion of the restoration measures carried out in the environment. It was hypothesized that a secondary disturbance, sustained by a high seasonal release of nutrients from the sediments, could create considerable deviations from the expected improvement in benthic conditions.     

The SWAP EUV Imaging Telescope Part I: Instrument Overview and Pre-Flight Testing

The Sun Watcher with Active Pixels and Image Processing (SWAP) is an EUV solar telescope onboard ESA’s Project for Onboard Autonomy 2 (PROBA2) mission launched on 2 November 2009. SWAP has a spectral bandpass centered on 17.4 nm and provides images of the low solar corona over a 54×54 arcmin field-of-view with 3.2 arcsec pixels and an imaging cadence of about two minutes. SWAP is designed to monitor all space-weather-relevant events and features in the low solar corona. Given the limited resources of the PROBA2 microsatellite, the SWAP telescope is designed with various innovative technologies, including an off-axis optical design and a CMOS–APS detector. This article provides reference documentation for users of the SWAP image data.     

In situ heavy metals (copper, lead and cadmium) in different plankton compartments and suspended particulate matter in two coupled Mediterranean coastal ecosystems (Toulon Bay, France)

We monitored the concentrations of copper, lead and cadmium in seawater, in suspended particulate matter (SPM) and in bacteria, phyto- and zooplankton communities separated from abiogenic particles, over a one year cycle in two coupled Mediterranean coastal ecosystems (Little Bay (LiB) and Large Bay (LaB)). Metals were present in seawater in the order Cu > Pb > Cd in both bays and showed important variations within the same month than among months. In LiB, their concentrations were between 0.62 and 2.82 μg Cu l⁻¹, 0.16 and 19 μg Pb l⁻¹ and 0.007 and 0.14 μg Cd l⁻¹, respectively, whereas in LaB, they were between 0.23 and 2.11 μg Cu l⁻¹, 0.09 and 0.76 μg Pb l⁻¹ and not detected and 0.65 μg Cd l⁻¹. SPM play an important role on metal adsorption, especially for copper. Bioaccumulation factors showed that bacteria and phytoplankton accumulate metals whereas zooplankton tends to biodiminish them in the plankton food web.