Microseismicity and focal mechanisms at the western termination of the North Anatolian Fault and their implications for continental tectonics

For seven weeks, a temporary network of 68 seismological stations was operated in Central Greece, in the region of Thessaly and Evia, located at the western termination of the North Anatolian Fault system. We recorded 510 earthquakes and computed 80 focal mechanisms. Seismic activity is associated with the NE–SW dextral North Aegean Fault, or with very young E–W-striking normal faults that are located around the Gulf of Volos and the Gulf of Lamia. The important NW–SE-striking faults bounding the Pilion, or the basins of Larissa and Karditsa, are not seismically active, suggesting that it is easier to break continental crust, creating new faults perpendicular to the principal stresses, than to reactivate faults that strike obliquely to the principal stress axes     

“The probable industrial origin of archaeological daub at an Iron Age site in northeast Thailand” (Parr and Boyd, 2002): A comment on the inappropriate application of geophysical and geochemical techniques to an archaeological question

Parr and Boyd (2002) used colorimetric analysis in combination with geophysical and geochemical techniques to estimate firing temperatures for archaeological daub from an Iron Age site in Thailand. They suggest that the daub was fired at high temperatures and, therefore, is indicative of kiln utilization and increased industrialization during that period in Thailand. They argue that the adoption of a multimethod analytical approach in which the combination of data derived from ICP‐MS, X‐ray diffraction, and magnetic susceptibility analyses of daub samples, coupled with microscopic and macroscopic examination of samples, enhances the accuracy of their interpretations. While they should be commended for attempting to substantiate their claims using many geophysical and geochemical techniques, their arguments are flawed by the misapplication of the techniques described and/or over‐interpretation of the data generated by such techniques. Therefore, Parr and Boyd's (2002:285) point about methodology (“that the combined interpretation of independent measures provides a better estimate of the original firing temperatures of the archaeological material than has hitherto been possible”) is made redundant by the lack of scientific rigor applied to the independent measures used for this study. © 2003 Wiley Periodicals, Inc.     

Composition and origin of holotype Al‐Cu‐Zn minerals in relation to quasicrystals in the Khatyrka meteorite

We investigated the khatyrkite–cupalite holotype sample, 1.2 × 0.5 mm across. It consists of khatyrkite (Cu,Zn)Al₂, cupalite (Cu,Zn)Al, and interstitial material with approximate composition (Zn,Cu)Al₃. All mineral phases of the holotype sample contain Zn and lack Fe that distinguishes them from khatyrkite and cupalite in the Khatyrka meteorite particles (Bindi et al. 2009 , 2011 , 2012 , 2015 ; MacPherson et al. 2013 ; Hollister et al. 2014 ). Neither highly fractionated natural systems nor geo‐ or cosmochemical processes capable of forming the holotype sample are known so far. The bulk chemistry and thermal history of khatyrkite–cupalite assemblage in the holotype sample hint for its possible industrial origin. Likewise, the aluminides in the Khatyrka meteorite particles may also be derived from industrial materials and mixed with extraterrestrial matter during gold prospecting in the Listvenitovy Stream valley.     

Ubiquitination and carbonylation as markers of oxidative-stress in Ruditapes decussatus.

Environmental pollutants, such as metals, are widespread in aquatic environments and can lead to the formation of reactive oxygen species (ROS). ROS are highly toxic in marine species since they can cause serious reversible and irreversible changes in proteins including ubiquitination and modifications such as carbonylation. This study aimed to confirm the potential of ubiquitination and carbonylation as markers of oxidative stress in the clam Ruditapes decussatus (Veneroida, Veneridae) exposed to cadmium (40 microg/L). After 21 days of exposure clams were dissected into gills and digestive gland. Cytosolic proteins of both tissues were separated by two-dimensional electrophoresis (2-D SDS-PAGE) and analysed by immunobloting. Higher ubiquitination and carbonylation levels were in digestive gland of contaminated organisms. These results confirm the potential of ubiquitination and carbonylation as a sensitive and specific marker of oxidative stress in marine bivalves. In this approach, changes in protein structure provide options for affinity selection of sub-proteomes for 2D SDS-PAGE, simplifying the detection of protein biomarkers using proteomic approach.     

Detoxification mechanisms in shrimp: comparative approach between hydrothermal vent fields and estuarine environments

Hydrothermal vents are extreme deep-sea habitats that, due to their singular features, still intrigue scientific communities. Swift growth rates and profuse biomass of biological communities can be observed, despite of their inherently unstable physical-chemical and toxic conditions, indicating that organisms inhabiting this environment must be well adapted to these inhospitable conditions. The caridean shrimp, Chorocaris chacei, Mirocaris fortunata and Rimicaris exoculata, together with bathymodiolid mussels, dominate the vent fauna along the Mid-Atlantic Ridge (MAR). Crustacean species are widely used as biological indicators of environmental alterations, since they play a key ecological role as planktivorous grazers, epibenthic scavengers or as prey species. The biological consequences of the hydrothermal metal-rich environment in shrimp species are still largely unknown. Therefore, the aim of this study was the determination of the metal levels (Ag, Cd, Cu, Fe, Mn and Zn), metallothioneins (MT) and lipid peroxidation (LPO) in shrimp species collected in Rainbow, Lucky Strike and Menez-Gwen vent sites, in order to evaluate their different adaptation strategies toward metals when compared with two common coastal shrimp species (Palaemon elegans and Palaemonetes varians) from a fairly unpolluted estuarine system in south Portugal (Ria Formosa). Results show significant differences in metal concentrations, MT levels and lipid peroxidation between vent and coastal shrimp and also between shrimp species from the same site. This indicates that biochemical responses in both vent and coastal shrimp are affected not only by the environmental characteristics but also by inter-specific differences. Nevertheless, these responses apparently grant a successful adaptation for the survival in a metal-extreme environment.     

Experimental biological effects assessment associated with on-shore brine discharge from the creation of gas storage caverns

Most of the studies on biological and ecological effects associated with brine discharge into the marine environment are related to the operation of desalination plants, for the production of freshwater. In this study we analysed the biological effects of a brine effluent from a completely different source, produced from the lixiviation of rock salt caves, for the creation of natural gas storage caverns. Lethal and sub-lethal endpoints following exposure to the brine were studied in a range of macrofauna species characteristic of the soft and hard bottom habitats in the vicinity of the discharge area, namely the isopod Eurydice pulchra, the annelids Sabellaria alveolata and Ophelia radiata, the sea-urchin Paracentrotus lividus and the bivalve Mytilus galloprovincialis. In a first series of experiments, brine, with salinity above 300, was diluted in distilled water to a salinity value close to that of the seawater in the discharge area (salinity 36) and, surprisingly, none of the exposed species was able to survive or develop into viable larvae. A second series of experiments exposed the species to brine diluted with seawater, simulating more realistic discharge circumstances. All the tested species at all the measured endpoints (adult survival, larval abnormal development, sperm fertilization success) showed negative biological effects in brine solutes always at a lower salinity than that of a salinity control obtained with concentrated seawater. The sub-lethal experiments with larval development of P. lividus, S. alveolata and M. galloprovincialis, and the fertilization success of P. lividus gave EC₅₀ values for the brine solute with salinity in the range of 40.9–43.5, whereas the EC₅₀ values for the concentrated seawater were in the range of salinity 44.2–49.0. It is hypothesised that differences in the ionic composition of the brine cause the inability of the species to tolerate the exposure to brine.     

Population succession and feeding of scyphomedusae, Aurelia aurita, in a eutrophic tropical lagoon in Taiwan

Seasonal dynamics and feeding of scyphomedusae, Aurelia aurita, were investigated monthly from 1999 to 2002 in relation to environmental conditions in Tapong Bay, a eutrophic tropical lagoon in southwestern Taiwan. Medusae appeared throughout the year but exhibited seasonal dynamics that were correlated with hydrographic features in the bay. Most ephyrae of A. aurita occurred mainly in the lower flushed and eutrophic inner bay, and during the cold, dry season between November and February. They grew to young medusae with a maximum abundance in spring (March–May), but their numbers abruptly decreased during the warm and rainy summer season in June–September. The remaining medusae then grew rapidly to a maximal size of 29 cm. Mature females spawned in the following autumn when precipitation decreased but zooplankton food was still abundant. These mature individuals decreased in size after spawning and in winter. Gut content analysis revealed that A. aurita fed mainly on copepods and copepod nauplii and less on bivalve larvae and fish eggs. Prey selectivity indices indicated that larger medusae selected positively for copepods while small size medusae preferred copepod nauplii. The overall feeding effect of A. aurita on the standing stock of zooplankton was significant (27%) in the bay. Our results suggest that tidal flow and dense oyster culture pens were the two most important factors influencing the spatial distribution pattern of A. aurita in the bay, while precipitation affected the population abundance seasonally; decreasing water temperature coincided with the mass release of ephyra in late autumn and winter.     

The Influence of the City of Athens on the Evolution of the Sea-Breeze Front

In the present study, we examine the dynamics of a sea-breeze front and the urban heat island interacting with the heavily urbanized city of Athens. For this reason, simulations were performed with a modified version of the PSU/NCAR Mesoscale Model (MM5), whereby urban features are considered, and the model results were compared with surface routine meteorological data. An unrealistic run was also performed, where the city of Athens was replaced by dry cropland and pasture surface, as in the surrounding area. A delay in the sea-breeze front was found during daytime, together with frictional retardation concerning its penetration, as well as inland displacement of the heat island as the air moved over the city of Athens. During nighttime, the wind speed increased over the lower atmosphere in the city centre due to the enhanced urban heat island.     

Synoptic-scale physical mechanisms associated with the Mei-yu front: A numerical case study in 1999

The Mei-yu front system occurring from 23 to 27 June 1999 consists of the Mei-yu front and the dewpoint front, which confine a warm core extending from the eastern flank of the Tibetan Plateau to the west of 145°E. To further understand the synopticscale physical mechanisms associated with the Mei-yu front system, the present study proposes another insight into the physical significance of the x-component relative vorticity (XRV) whose vertical circulation is expected to tilt isentropic surfaces. The XRV equation diagnoses exhibit that the twisting effect of the planetary vorticity (TEPV) is positive along the Mei-yu front and negative in the dewpoint front region, and tilts isentropic surfaces from south to north in the Mei-yu frontal zone. Conversely, the meridional gradient of the atmospheric buoyancy (MGAB) tilts isentropic surfaces in the opposite direction and maintains negative in the regions where the TEPV is positive and vice versa. Thus, the TEPV plays the role of the Mei-yu frontogenesis, whereas the MGAB demonstrates the Meiyu frontolysis factor. Both terms control the evolution of the cross-front circulation. The other terms show much minor contributions in this case study. The present simulations also indicate that the weakening of the upper-level jet evidently induces the weakening of the Mei-yu front and reduces the amplitude of the East Asia cold trough. Furthermore, the impact can also penetrate into the lower troposphere in terms of mesoscale disturbances and precipitation, proving that the upper-level jet imposes a noticeable top-down influence on the Mei-yu front system.