The Variscan basement in the western shoulder of the Lusitanian Basin (West Iberian Margin): insights from detrital-zircon geochronology of Jurassic strata

There is no consensus about the geological nature of the westernmost portion of the Iberian Massif. In the present research, the detrital zircon U–Pb signatures of Jurassic strata of the Lusitanian Basin, known to be west-sourced, are combined with published U–Pb data for the Precambrian-Palaeozoic basement and other Lusitanian Basin units to better understand this poorly exposed portion of the Iberian Massif. Cryogenian to Ediacaran ages prevail in a northern Upper Jurassic unit, while Lower and Upper Jurassic rocks in southern locations yield mostly Carboniferous to upper Permian zircons. These age results, coupled with their respective U/Th ratios, suggest that the basin covers two distinct terranes of the Iberian Massif. Another noteworthy feature of west-derived deposits is the abundance of < 310 Ma ages. It is proposed that a combination of crustal thinning in the West Iberian Margin with regional eastward basement tilt, favoured the enrichment of relatively young zircon in the western shoulder of the basin relative to its eastern margin. The detrital zircon age signatures also reveal a middle to late Permian thermal event in restricted areas, which is probably associated with the oldest stages of Alpine extension in West Iberia. // Actualmente no existe consenso sobre la naturaleza geológica de la zona más occidental del Macizo Ibérico. En la presente investigación se ha llevado a cabo un análisis de la relación entre la signatura U-Pb de circones detríticos obtenidos en estratos jurásicos de la Cuenca Lusitana, provenientes del oeste, con datos de U-Pb publicados sobre el basamento Precámbrico-Paleozoico y otras formaciones de la Cuenca Lusitana, para comprender mejor esta zona poco expuesta del Macizo Ibérico. Las edades criogénicas y ediacarienses dominan en la parte norte de las unidades del Jurásico superior, mientras que en la parte sur dominan los circones de edades carboníferas y del Pérmico superior, tanto en las unidades del Jurásico inferior como en las del superior. Estos resultados geocronológicos junto con sus respectivas relaciones U/Th, sugieren que la cuenca cubre dos terrenos distintos del Macizo Ibérico. Otra característica notable de los depósitos procedentes del oeste es la abundancia de edades <310 Ma. Se propone que una combinación de adelgazamiento de la corteza en el Margen Ibérico Occidental junto con la inclinación regional del basamento hacia el este, favoreció el enriquecimiento de circones relativamente jóvenes en el flanco occidental de la cuenca en relación con su margen oriental. Las signaturas de edad del circón detrítico también revelan un evento térmico del Pérmico medio al tardío en áreas restringidas que probablemente esté asociado con las etapas más antiguas de extensión alpina en el oeste de Iberia

Artificial light pollution influences behavioral and physiological traits in a keystone predator species, Concholepas concholepas

Artificial Light At Night (ALAN) is an increasing global problem that, despite being widely recognized in terrestrial systems, has been studied much less in marine habitats. In this study we investigated the effect of ALAN on behavioral and physiological traits of Concholepas concholepas, an important keystone species of the south-eastern Pacific coast. We used juveniles collected in intertidal habitats that had not previously been exposed to ALAN. In the laboratory we exposed them to two treatments: darkness and white LED (Lighting Emitting Diodes) to test for the impacts of ALAN on prey-searching behavior, self-righting time and metabolism. In the field, the distribution of juveniles was observed during daylight-hours to determine whether C. concholepas preferred shaded or illuminated microhabitats. Moreover, we compared the abundance of juveniles collected during day- and night-time hours. The laboratory experiments demonstrated that juveniles of C. concholepas seek out and choose their prey more efficiently in darkened areas. White LED illuminated conditions increased righting times and metabolism. Field surveys indicated that, during daylight hours, juveniles were more abundant in shaded micro-habitats than in illuminated ones. However, during darkness hours, individuals were not seen to aggregate in any particular microhabitats. We conclude that the exposure to ALAN might disrupt important behavioral and physiological traits of small juveniles in this species which, as a mechanism to avoid visual predators, are mainly active at night. It follows that ALAN in coastal areas might modify the entire community structure of intertidal habitats by altering the behavior of this keystone species

Effects of physical exercise in biochemical parameters and dorsolateral prostate lesions: data from a rat model of prostate cancer

Background: Prostate cancer (PCa) is among the most prevalent cancers worldwide. Physical exercise is widely recognized due to its beneficial effects. This study aimed to evaluate the effects of physical exercise on biochemical pa- rameters and in dorsolateral prostate lesions in a rat model of PCa. Materials and Methods: Ninety-five male Wistar Unilever rats were randomly divided into eight groups sacrificed at 35 (groups I) or 61 weeks of age (groups II): control sedentary groups (Cont+Sed I (n = 10); Cont+Sed II (n = 10)); induced sedentary group (PCa+Sed I (n = 10); PCa+Sed II (n = 15)); control exercised groups (Cont+EX I (n = 10); Cont+EX II (n = 10)) and induced exercised groups (PCa+EX I (n = 10); PCa+EX II (n = 20)). All procedures were approved (DGAV, no. 021326). Animals from exercised groups started the exer- cise program in a treadmill at 8 weeks of age, for 28 weeks or 53 weeks. The animals were trained 5 days/week, 60 min per day. Prostate lesions were induced at 12 weeks of age, with sequential administration of flutamide, testosterone propion- ate and N-methyl-N-nitrosourea, and subcutaneous implants of crystalline testosterone. Animals were sacrificed at 35 or 61 weeks of age. Peripheral blood of all animals was col- lected by intracardiac puncture. A complete necropsy was performed. The dorsolateral prostate tissues sections were processed for histological analysis. Data were analysed using SPSS 25. p 0.05). Dorsolateral prostate lesions were classified as dysplasia, prostatic intraep- ithelial neoplasia (PIN) and microinvasive carcinoma. The number of prostate lesions was higher in animals from groups II than in those from groups I, mainly in PCa+Sed II animals when compared with PCa+Sed I (p 0.05). Conclusions: Overall, the animals sacrificed at 61 weeks of age developed more dorsolateral prostate lesions than ani- mals sacrificed at 35 weeks of age, which may be related to a longer testosterone exposure

Speciation and fate of trace metals in estuarine sediments under reduced and oxidized conditions, Seaplane Lagoon, Alameda Naval Air Station (USA)

We have identified important chemical reactions that control the fate of metal-contaminated estuarine sediments if they are left undisturbed (in situ) or if they are dredged. We combined information on the molecular bonding of metals in solids from X-ray absorption spectroscopy (XAS) with thermodynamic and kinetic driving forces obtained from dissolved metal concentrations to deduce the dominant reactions under reduced and oxidized conditions. We evaluated the in situ geochemistry of metals (cadmium, chromium, iron, lead, manganese and zinc) as a function of sediment depth (to 100 cm) from a 60 year record of contamination at the Alameda Naval Air Station, California. Results from XAS and thermodynamic modeling of porewaters show that cadmium and most of the zinc form stable sulfide phases, and that lead and chromium are associated with stable carbonate, phosphate, phyllosilicate, or oxide minerals. Therefore, there is minimal risk associated with the release of these trace metals from the deeper sediments contaminated prior to the Clean Water Act (1975) as long as reducing conditions are maintained. Increased concentrations of dissolved metals with depth were indicative of the formation of metal HS(- )complexes. The sediments also contain zinc, chromium, and manganese associated with detrital iron-rich phyllosilicates and/or oxides. These phases are recalcitrant at near-neutral pH and do not undergo reductive dissolution within the 60 year depositional history of sediments at this site. The fate of these metals during dredging was evaluated by comparing in situ geochemistry with that of sediments oxidized by seawater in laboratory experiments. Cadmium and zinc pose the greatest hazard from dredging because their sulfides were highly reactive in seawater. However, their dissolved concentrations under oxic conditions were limited eventually by sorption to or co-precipitation with an iron (oxy)hydroxide. About 50% of the reacted CdS and 80% of the reacted ZnS were bonded to an oxide-substrate at the end of the 90-day oxidation experiment. Lead and chromium pose a minimal hazard from dredging because they are bonded to relatively insoluble carbonate, phosphate, phyllosilicate, or oxide minerals that are stable in seawater. These results point out the specific chemical behavior of individual metals in estuarine sediments, and the need for direct confirmation of metal speciation in order to constrain predictive models that realistically assess the fate of metals in urban harbors and coastal sediments

Endogenous cycles, activity patterns and energy expenditure of an intertidal fish is modified by artificial light pollution at night (ALAN)

The increase of global light emissions in recent years has highlighted the need for urgent evaluation of their impacts on the behaviour, ecology and physiology of organisms. Numerous species exhibit daily cycles or strong scototaxic behaviours that could potentially be influenced if natural lighting conditions or cycles are disrupted. Artificial Light Pollution at Night (ALAN) stands for situations where artificial light alters natural light-dark cycles, as well as light intensities and wavelengths. ALAN is increasingly recognized as a potential threat to biodiversity, mainly because a growing number of studies are demonstrating its influence on animal behaviour, migration, reproduction and biological interactions. Most of these studies have focused on terrestrial organisms and ecosystems with studies on the effects of ALAN on marine ecosystems being more occasional. However, with the increasing human use and development of the coastal zone, organisms that inhabit shallow coastal or intertidal systems could be at increasing risk from ALAN. In this study we measured the levels of artificial light intensity in the field and used these levels to conduct experimental trials to determine the impact of ALAN on an intertidal fish. Specifically, we measured ALAN effects on physiological performance (oxygen consumption) and behaviour (activity patterns) of “Baunco” the rockfish Girella laevifrons, one of the most abundant and ecologically important intertidal fish in the Southeastern Pacific littoral. Our results indicated that individuals exposed to ALAN exhibited increased oxygen consumption and activity when compared with control animals. Moreover, those fish exposed to ALAN stopped displaying the natural (circatidal and circadian) activity cycles that were observed in control fish throughout the experiment. These changes in physiological function and behaviour could have serious implications for the long-term sustainability of fish populations and indirect impacts on intertidal communities in areas affected by ALAN

The changing carbon cycle of the coastal ocean

The carbon cycle of the coastal ocean is a dynamic component of the global carbon budget. But the diverse sources and sinks of carbon and their complex interactions in these waters remain poorly understood. Here we discuss the sources, exchanges and fates of carbon in the coastal ocean and how anthropogenic activities have altered the carbon cycle. Recent evidence suggests that the coastal ocean may have become a net sink for atmospheric carbon dioxide during post-industrial times. Continued human pressures in coastal zones will probably have an important impact on the future evolution of the coastal ocean's carbon budget