Seismic hazard analysis in zones of time and space interdependence: An application to São Miguel Island,Azores

The Azores Islands are located in the mid-Atlantic region near the triple junction where the Euro-Asiatic-African-American plates join together. Seismic activity in the area is very high, as can be observed either from historical events since the fifteenth century, from present day microseismicity, and from direct and indirect measurements of recent tectonic deformation. Volcanic activity is also present throughout the region. All available information, even data exhibiting low quality, was used to develop hazard models of São Miguel Island. Source zones were established based on both the global tectonic behaviour of the region and on the local active fault structures. Recurrence laws for São Miguel Island, for which historical information seemed quite incomplete, were obtained from the large events in the entire archipelago and from their remarkable pattern of time and space dependence, and complimented by information on long-term fault deformation (for the longer recurrence periods) and on high precision instrumental network (for the very short recurrence periods). Attenuation laws were derived from data on events felt and/or recorded in the Island. Hazard maps were obtained through a modified version of McGuire's algorithm for several geometries of source areas and results compared with the maximum observed intensity of historical events.     

Benthic primary producers--a neglected environmental problem in Mediterranean maricultures?

Marine fish farming is increasing rapidly in the Mediterranean and in contrast to the Atlantic the coastal zone in the Mediterranean is characterized by clear waters with high transparency. This allows benthic primary producers such as the slow-growing seagrass Posidonia oceanica to grow at large depths at locations suitable for fish farming and generating a conflict between the conservation of these meadows and the growth of aquaculture operations in the Mediterranean. In this paper we review the current knowledge on environmental interactions between fish farming and benthic primary producers with particular focus on P. oceanica, as this seagrass is a key component along Mediterranean coasts. The recovery times of P. oceanica are very long, in the order of centuries, and losses of this species are thus considered to be irreversible at managerial time scales.     

Trophic Assessment in Chinese coastal systems-review of methods and application to the Changjiang (Yangtze) Estuary and Jiaozhou Bay

Coastal eutrophication has become one of the main threats to Chinese coastal areas during the last two decades. High nutrient loads from human activities have modified the natural background water quality in coastal water bodies, resulting in a range of undesirable effects. There is a need to assess the eutrophic level in coastal systems and to identify the extent of this impact to guide development of appropriate management efforts. Traditional Chinese assessment methods are discussed and compared with other currently-used methods, such as the Oslo-Paris Convention for the Protection of the North Sea (OSPAR) Comprehensive Procedure and Assessment of Estuarine Trophic Status (ASSETS). The ASSETS method and two Chinese methods were tested on two Chinese systems: the Changjiang (Yangtze) Estuary and Jiaozhou Bay. ASSETS is process based, and uses a pressure-state-response model based on three main indices: Influencing Factors, Overall Eutrophic Condition, and Future Outlook. The traditional methods are based on a nutrient index. ASSETS was successfully applied to both systems, classifying the Changjiang Estuary as Bad (high eutrophication) and Jiaozhou Bay as High (low eutrophication). The traditional methods led to ambiguous results, particularly for Jiaozhou Bay, due to the high spatial variability of data and a failure to assess the role of shellfish aquaculture in nutrient control. An overview of the Chinese coastal zone identifies 50 estuaries and bays that should form part of a national assessment. A comparison of methods and results suggests that ASSETS is a promising tool for evaluating the eutrophication status of these systems.     

Impact of submarine hydrothermal vents on the metal composition of krill and its excretion products

We have measured the metal composition and estimated the excretion rate of trace elements (Ag, Cd, Co, Cu, Ni, Pb, V and Zn) by Antarctic krill (Euphausia superba) in three locations (two located within a submarine hydrothermal vent field and one away from it) along the Antarctic Peninsula region of the Southern Ocean. Results indicated that krill excreted large amounts of Ag, Cu, Pb and Zn, (range: 1.9–41.2 pmol Ag g DW^? 1 h^? 1, 15.3–26.8 nmol Cu g DW^? 1 h^? 1, 308.7–1118.3 pmol Pb g DW^? 1 h^? 1 and 24.4–76.5 nmol Zn g DW^? 1 h^? 1), compared with the non-significant or undetectable release rates of Cd, Co, Ni and V. The metal composition of the excreted material from krill collected in the area of hydrothermal activity was similar to the metal composition reported for suspended particles emitted from those vents. Our results suggest that krill recycling of Ag, Cu, Pb and Zn could potentially influence trace metal concentrations in the water column of the Bransfield region of the Southern Ocean, and that the original source of metals to these waters may be hydrothermal vents.     

Removal of phenolic compounds in olive mill wastewater by silica–alginate–fungi biocomposites

This study aims to attempt a treatment strategy based on fungi immobilized on silica-alginate (biocomposites) for removal of phenolic compounds in olive oil mill wastewater (OMW), OMW supplemented (OMWS) with phenolic compounds and water supplemented (WS) with phenolic compounds, thus decreasing its potential impact in the receiving waters. Active (alive) or inactive (death by sterilization) Pleurotus sajor caju was encapsulated in alginate beads. Five beads containing active and inactive fungus were placed in a mold and filled with silica hydrogel (biocomposites). The biocomposites were added to batch reactors containing the OMW, OMWS and WS. The treatment of OMW, OMWS and WS by active and inactive biocomposites was performed throughout 28 days at 25 °C. The efficiency of treatment was evaluated by measuring the removal of targeted organic compounds, chemical oxygen demand (COD) and relative absorbance ratio along the time. Active P. sajor caju biocomposites were able to remove 64.6–88.4 % of phenolic compounds from OMW and OMWS and 91.8–97.5 % in water. Furthermore, in the case of OMW there was also a removal of 30.0–38.1 % of fatty acids, 68.7 % of the sterol and 35 % of COD. The silica–alginate–fungi biocomposites showed a high removal of phenolic compounds from OMW and water. Furthermore, in the application of biocomposites to the treatment of OMW it was observed also a decrease on the concentration of fatty acids and sterols as well as a reduction on the COD.     

Radiating spherical collapse with shear and heat flow

We consider a spherical body consisting of a fluid with heat flow which radiates in its exterior a null fluid described by the outgoing Vaidya's metric, we prove that this solution matched with the outgoing Vaidya's metric represents a physically reasonable collapsing model. Our model has the remarkable property: it is shear-free and the motion of the fluid is geodesic.CNPq-allowance.     

Climate change projections of the North American Regional Climate Change Assessment Program (NARCCAP)

We investigate major results of the NARCCAP multiple regional climate model (RCM) experiments driven by multiple global climate models (GCMs) regarding climate change for seasonal temperature and precipitation over North America. We focus on two major questions: How do the RCM simulated climate changes differ from those of the parent GCMs and thus affect our perception of climate change over North America, and how important are the relative contributions of RCMs and GCMs to the uncertainty (variance explained) for different seasons and variables? The RCMs tend to produce stronger climate changes for precipitation: larger increases in the northern part of the domain in winter and greater decreases across a swath of the central part in summer, compared to the four GCMs driving the regional models as well as to the full set of CMIP3 GCM results. We pose some possible process-level mechanisms for the difference in intensity of change, particularly for summer. Detailed process-level studies will be necessary to establish mechanisms and credibility of these results. The GCMs explain more variance for winter temperature and the RCMs for summer temperature. The same is true for precipitation patterns. Thus, we recommend that future RCM-GCM experiments over this region include a balanced number of GCMs and RCMs.     

Seismic hazard analysis in zones of time and space interdependence: An application to S?o Miguel Island, Azores

The Azores Islands are located in the mid-Atlantic region near the triple junction where the Euro-Asiatic-African-American plates join together. Seismic activity in the area is very high, as can be observed either from historical events since the fifteenth century, from present day microseismicity, and from direct and indirect measurements of recent tectonic deformation. Volcanic activity is also present throughout the region.All available information, even data exhibiting low quality, was used to develop hazard models of São Miguel Island. Source zones were established based on both the global tectonic behaviour of the region and on the local active fault structures. Recurrence laws for São Miguel Island, for which historical information seemed quite incomplete, were obtained from the large events in the entire archipelago and from their remarkable pattern of time and space dependence, and complimented by information on long-term fault deformation (for the longer recurrence periods) and on high precision instrumental network (for the very short recurrence periods).Attenuation laws were derived from data on events felt and/or recorded in the Island.Hazard maps were obtained through a modified version of McGuire's algorithm for several geometries of source areas and results compared with the maximum observed intensity of historical events.Abstract presented at the 21st General Assembly of the European Seismological Commission held in Sofia, 1988.