Biochemical indicators of contaminant exposure in spotted pigfish (Orthopristis ruber) caught at three bays of Rio de Janeiro coast

The initial sampling in the Marine Monitoring Program (MOMAM), coordinated by the Ministry of Marine Affairs (IEAPM), was performed along the southeast coast of Brazil. Orthopristis ruber samples were collected at Guanabara, Sepetiba and Ilha Grande Bays. Microsomal CYP1A levels and cytosolic cholinesterase (ChE), catalase (CAT) and glutathione S-transferase (GST) activities were measured in the liver of these fish according to established procedures. CAT activity and CYP1A content were significantly higher (P < or = 0.05) in fish caught at Guanabara Bay, which might be due to higher levels of peroxisome proliferators and Ah receptor agonists, respectively, at this site compared to the other sites. Also, lower GST activity was observed in fish from this site, which may possibly be related to the presence of oxidative-stress inducing compounds.     

Climate variability and planktonic communities: The effect of an extreme event (severe drought) in a southern European estuary

As a consequence of climate change, flood and drought events are increasing in frequency throughout the world. Nevertheless, knowledge of the effects on zooplankton estuarine communities is still scarce. The present study aimed to examine zooplankton ecology over two contrasting environmental conditions: regular years and extreme dry years, in a shallow temperate southern European estuary, the Mondego Estuary (Portugal). Monthly samples were carried out during three consecutive years: 2003 characterized as a regular temperate year concerning precipitation and river flow, and an extremely dry period during 2004–2005. The spatial and temporal structure of the biological data was evaluated by a three-mode principal component analysis (PCA), which allowed us to distinguish three distinct ecological areas based on their biological composition and their relationship with hydrologic parameters. The severe drought in 2004–2005 was responsible for spatial shifts in the estuary regarding zooplankton community and interannual variability, with an increase in abundance and diversity during the period of low freshwater flow. This freshwater flow regime influenced the composition of the zooplankton community at the most upstream section of Mondego estuary (zone 3), with a replacement of the freshwater community by one predominantly dominated by estuarine organisms. The occurrence of such estuarine community contributed to the increase in zooplankton abundance which is ascribed to the estuarine species Acartia tonsa. The comparison with previous data obtained for this estuarine ecosystem, demonstrated the occurrence of a different scenario at times of high freshwater flow, being defined the existence of two sub-estuarine systems, the north and south arm, presenting the south one the highest values of abundance.     

Extreme values and meteorology

Summary The basic ideas of univariate extremes and some applications are described in the paper; some references are made to multivariate extremes and stochastic processes of extremes.

---

Zusammenfassung Es werden einige grundlegende Ideen zu univariaten Extremen und ihren Anwendungen beschrieben. Multivariate Extreme und stochastische Prozesse von Extremen werden ebenfalls besprochen.

---

---

With 4 Figures     

Elemental and isotopic geochemistry in the hydrothermal area of Chaves,Vila Pouca de Aguiar (northern Portugal)

Chaves thermal waters (76°C) are the most important external manifestations of low-temperature geothermal systems occurring in Portuguese mainland. They are related to crystalline granitic rocks. This paper describes the use of the environmental isotopic composition (oxygen-18, deuterium, and tritium) of hot and cold waters of the Chaves area as an important hydrogeological tool to solve specific problems arising in the appraisal of the geothermal resources of the area (e.g., origin and age of waters, recharge area, and underground flow paths).¹⁸O and D analyses seem to confirm the meteoric origin of Chaves thermal waters. The local altitude dependence of meteoric waters was determined by¹⁸O and D analyses of superficial and shallow groundwaters of the Chaves plain and its bordering mountains. Chaves thermal waters seem to be related to meteoric waters, infiltrated on the highest topography areas (Bolideira granitic outcrop NE Chaves), that percolate at great depth and emerge in a discharge area at lower altitude (Chaves plain). Chaves thermal waters showing little oxygen-18 shift and low tritium concentrations could be considered external manifestations of an old geothermal system in which the isotopic water-rock interaction is adjusted to equilibrium.     

Reproductive synchrony in a diverse Acropora assemblage,Vamizi Island,Mozambique

Multi‐specific synchronous spawning has never been documented for East Africa, but coral spawn‐slicks are observed annually around Vamizi Island, Northern Mozambique. We monitored gamete development in Acropora species from July 2012 to October 2013 and from August to September 2014 to describe patterns of reproductive seasonality and synchrony within and amongst species of Acropora. Gamete maturation was highly synchronized within and amongst Acropora species and culminated in multi‐specific spawning events lasting 1–3 nights in each year of the study, in late August or September. In 2013 and 2014, 50% or more of the colonies of over 50% of the species sampled prior to the spawning events had mature gametes. In all years, 91–99% colonies sampled after the spawning events had no visible gametes. The percentage of colonies with mature gametes was up to 100% for some species. In other species, the absence of mature gametes throughout the study period indicates that they might not spawn in certain years. The analysis of a 8‐year record of observations of spawn‐slicks showed that spawning generally occurred once a year for a few consecutive days between September and December, during periods of rising sea surface temperature and low wind speed and rainfall. This study is the first to quantitatively document coral reproduction in Mozambique and multi‐specific synchronous spawning off the coast of Africa. These findings contrast with the asynchronous breeding reported for Kenyan reefs and support the absence of breakdown in coral reproductive synchrony towards low latitudes.     

Physical models of rifting and transform faulting, due to ridge push in a wedge-shaped oceanic lithosphere

By scaled physical modelling, we have investigated the mechanical response to gravitational forces in an oceanic lithosphere, overlying a less dense asthenosphere. In the models, an upper wedge-shaped layer of sand represented an oceanic lithosphere (0–35 Ma old, with a half-spreading velocity of 3 cm/yr), and a lower layer of polydimethylsiloxane (PDMS), mixed with dense wolframite powder, represented the asthenosphere. In the models, as in nature, isostatic compensation resulted in uplift of ridges and subsidence on their flanks. The resulting relief was responsible for ridge push. We tested two main configurations: straight ridges and offset ridges. In all the models, ridge push was sufficient to cause plate motion, underlying advection, and symmetrical rifting at the ridge axis. There was no need to impose plate motions through external pistons and motors. In models of straight ridges, the style of normal faults in the axial rift zone depended on the local thickness of the brittle sand layer. For thick layers, normal faults rafted out from the active zone of rifting, creating a fossil topography of tilted blocks, between faults dipping toward the ridge. In a model of an offset ridge, with thin lithosphere at the ridge crest and no embedded weakness, ridge push was responsible for a short transform fault, linking en-échelon rifts. In a similar model, but with thick lithosphere, an oblique rift formed at about 20° to the offset trace. We conclude that ridge push was not adequate to create an ideal transform fault. In a model of an offset ridge, with an embedded thin vertical layer of pure PDMS at 90° to the ridge, transform motion concentrated along this weak layer, and the resulting structural style was very similar to that in nature. On the basis of these results, we infer that, in nature, (1) ridge push can indeed drive plate motion, and (2) ridge push can drive strike-slip motion on transform faults, provided that these are weaker than the adjacent oceanic lithosphere and that they form early in the history of spreading.     

Effects of topography on the curvature of fold-and-thrust belts during shortening of a 2-layer model of continental lithosphere

We have used analogue experiments to investigate the effects of surface topography on the curvature of fold-and-thrust belts, under conditions of (1) initial relief, but no erosion, and (2) no initial relief, but differential erosion, sedimentation and transport.In experiments where a 2-layer model lithosphere shortened and thickened in front of an advancing straight piston, the geometry of the developing thrust wedge was very sensitive to variations in surface topography. In models with an initially flat, horizontal surface, and in the absence of erosion and sedimentation, thrusts were straight, propagated forwards, and nucleated at buckle folds far in front of an advancing piston. Around an initial topographic high (plateau or cone), thrusts tended to be arcuate, forming salients towards the foreland. Initial plateaux and cones tended to behave rigidly, while arcuate thrust slices formed around them. To accommodate differential slip, transfer zones developed on both sides of initial highs. Fault blocks rotated about vertical axes and thrusts moved in oblique slip within transfer zones. In models with initially horizontal surfaces, which were subject to differential erosion, sedimentation and transport, thrusts initially were straight, but then progressively rotated around non-eroded, thickened and stronger areas. These worked as indenters, in front of which new thrusts nucleated at curved buckle folds. These thrusts were also curved, their apices being in front of the thickened, non-eroded areas.In nature, arcuate structural patterns are to be found around the Altiplano of the Central Andes and around the Tromen volcanic ridge in the Neuquén Basin of northern Patagonia. We infer that these areas behaved in quasi-rigid fashion, protected as they were by their high elevations, and that differential erosion at the scale of the entire Andes may have contributed to oroclinal bending.     

Lichen-Transplant Biomonitoring in the Assessment of Dispersion of Atmospheric Trace-Element Pollutants: Effects of Orientation Towards the Wind Direction

Transplants of the epiphytic lichen Parmelia sulcata were suspended in nylon bags in a special device allowing a fixed orientation of the lichen towards the wind direction, viz. facing the wind (F orientation) or shielded from the wind by its substrate (T orientation). The F- and T-orientation data were mutually compared and also with reference values (= time zero values of the transplants). The data were analysed via Monte Carlo added target transformation factor analysis (MCATTFA) to get information on possible emission-source profiles and their contributions to total-element levels in transplants, in F- and T-orientations. Both orientations did not differ for Na, Mg, P, Cl, K, Fe, Co, Ni, Ga, Se, Br, Sr, Ba, La, Nd, Sm, Lu and Ta, but showed some time-related differences for Cr and Zn. For the remaining elements the data presents a high variability. Under the conditions of the experiment, F- and T-oriented transplants generally did not result in differences in source profiles reflected, nor in differences in source contributions to element levels in the transplants.     

2-D rotation behavior of a rigid ellipse in confined viscous simple shear: numerical experiments using FEM

The rotation behavior of rigid elliptical inclusions adherent to the viscous matrix in simple shear flow is investigated using a 2-D finite element numerical model. Several simulations were performed using different ratios (S) between shear zone width and inclusion's least principal axis. A computational strategy was devised to calculate pressure and viscous forces exerted on the inclusion and deduce its angular velocity. For large S values, results agree remarkably well with theoretical predictions, while for small S values results deviate significantly from theory but are in agreement with previous analogue experiments. The numerical model provided detailed and coherent information about the physical parameters involved in the process (e.g., pressure, strain rate and vorticity distributions within the model).