Ecological classification of European transitional waters in the North-East Atlantic eco-region

A new methodology to classify European North-East Atlantic transitional waters into ecological types has been developed based on the most important hydrological and morphological features that are likely to determine the ecology of aquatic systems in transitional waters. Hydrological indicators help identifying if a transitional water area is dominated by fresh or sea water and/or by intertidal or subtidal areas, while morphological indicators allow an estimation of the complexity of the transitional water and the diversity of the habitats involved. Twelve transitional waters of the southern Bay of Biscay were classified using this methodology and the five hydro-morphological types obtained were validated with benthic macro-invertebrate data. Transitional waters with a complex morphology showed the highest values of species diversity, while those with a smaller tidal influence showed lower species diversity. The ‘Scrobicularia’ and ‘Abra’ assemblages, previously identified in the study area, were found to be related to different types of transitional waters. The ‘Abra’ assemblage only appeared in estuaries with a complex morphology and dominated by tidal influences, while the ‘Scrobicularia’ assemblage was detected in all the transitional waters except for a single coastal lagoon. This classification of transitional waters may therefore be useful to establish the biological reference conditions needed for European Directives.     

Ecosystem-based management institutional design: Balance between federal,state, and local governments within the Gulf of Mexico Alliance

We present a case study of the organizational framework of the Gulf of Mexico Alliance (GOMA), which was implemented to promote the use of ecosystem-based management (EBM) at a regional level. GOMA is a state-led initiative formed to protect and restore coastal and marine resources of the Gulf of Mexico. Representatives of the US Gulf States, together with their federal partners, clearly defined ecological, social, and economic short- and long-term objectives to be reached through regional collaborations. The aim of this paper is to show how GOMA, and particularly the Ecosystem Integration and Assessment Priority Issue Team, in its attempt to apply ecosystem approaches to manage marine resources, modified the common organizational scheme by implementing partnerships at various governmental (federal, state, local) and nongovernmental levels. We address the following major points considered to be of importance for EBM implementation: (1) multilevel cooperation, (2) stakeholders’ involvement, (3) sharing of information, (4) bridging science and policy, and (5) consensus-based decision making.     

Paleoweathering features in the Sergi Formation (Jurassic-Cretaceous), northeastern Brazil,and implications for hydrocarbon exploration

Paleoweathering in the Sergi Formation has been classified and analyzed to ascertain its origin and relationship with stratigraphic evolution. The Sergi Formation belongs to the pre-rift sequence of the Recôncavo Basin (northeastern Brazil) and comprises a complex association of eolian and fluvial sandstones and lacustrine mudstones. This formation can be subdivided into three depositional sequences bounded by regional unconformities. Four paleoweathering types, each one related to a distinct origin, have been described in the Sergi Formation: (1) textural mottling, which is distinguished by alternating rock colors as a result of the iron oxide mobilization within mineral phases that evolved under alternating oxidation (yellowish, brownish and reddish shades) and reduction (grayish or greenish hues) conditions; (2) non-textural mottling, which displays a discoloration pattern that is independent of the original rock texture; (3) carbonate concentrations, usually related to carbonate nodule formation, which display a massive internal structure that reveals their origin through continuous growth or crystallization; and (4) banded carbonates (silicified), associated with the beginning of regular surface formation due to the chemical precipitation of carbonates within lacustrine environments. Both mottling color motifs and carbonate accumulation usually represent groundwater oscillation rather than pedogenesis. Only carbonate intraclasts and banded carbonate (silicified) have their origin ascribed to pedogenesis sensu stricto, although the carbonate intraclasts do not represent soil deposits in situ, but calcretes eroded from areas close to channels, and the banded carbonates (silicified) have strong diagenetic modifications. Therefore, it is reasonable to assume that fluvial and meteoric water have controlled paleoweathering evolution as well as deposition, yet both aspects are ruled by the same mechanisms (relief, sedimentation rate and, above all, climate).     

An overview of the Gulf of Batabanó (Cuba): Environmental features as revealed by surface sediment characterisation

The main environmental features of the Gulf of Batabanó, Cuba, Caribbean, were investigated through the analyses of surface sediments collected at 23 sites. In order to highlight the potential threats affecting the sedimentary compartment of this area, samples were analysed for: granulometry, mineralogy, heavy metals concentration (As, Cd, Cu, Mn, Ni, Pb, Zn), organic carbon, total nitrogen and radionuclides. Findings were compared with published data and “grey” literature.Results showed: granulometric homogeneity and a widespread carbonatic condition all over the gulf, probably due to stable bathymetry and lack of terrigenous input (except for the La Coloma basin); a rather pristine environment for what concerns heavy metals pollution, except for La Coloma where a large arsenic input was recorded; very low levels of natural and artificial radioactivity; a relevant quantity of sedimentary organic matter, providing biota with useful substrate for feeding and enhancing the food-web development while indirectly supplying lobster fisheries. Combined data highlighted the impact of the Dique Sur in reducing terrigenous input in the coastal area.Future studies should focus on dating of sediment cores for identifying and quantifying the changes acting in the gulf and on investigating the origins of the large arsenic input to La Coloma.     

Trends,drivers and impacts of changes in swidden cultivation in tropical forest-agriculture frontiers: A global assessment

This meta-analysis of land-cover transformations of the past 10–15 years in tropical forest-agriculture frontiers world-wide shows that swidden agriculture decreases in landscapes with access to local, national and international markets that encourage cattle production and cash cropping, including biofuels. Conservation policies and practices also accelerate changes in swidden by restricting forest clearing and encouraging commercial agriculture. However, swidden remains important in many frontier areas where farmers have unequal or insecure access to investment and market opportunities, or where multi-functionality of land uses has been preserved as a strategy to adapt to current ecological, economic and political circumstances. In some areas swidden remains important simply because intensification is not a viable choice, for example when population densities and/or food market demands are low. The transformation of swidden landscapes into more intensive land uses has generally increased household incomes, but has also led to negative effects on the social and human capital of local communities to varying degrees. From an environmental perspective, the transition from swidden to other land uses often contributes to permanent deforestation, loss of biodiversity, increased weed pressure, declines in soil fertility, and accelerated soil erosion. Our prognosis is that, despite the global trend towards land use intensification, in many areas swidden will remain part of rural landscapes as the safety component of diversified systems, particularly in response to risks and uncertainties associated with more intensive land use systems.     

The last deglaciation in the Picos de Europa National Park (Cantabrian Mountains,northern Spain)

A sedimentological and geochemical study of the Lago Enol sequence (Cantabrian Mountains, northern Spain), together with detailed geomorphological mapping, provides a first record of glacier evolution and climate change over the last 40 ka in the Picos de Europa National Park. The Enol glacier retreated from its maximum extent prior to 40 ka BP as demonstrated by the onset of proglacial lacustrine sedimentation in two glaciated depressions: the Comella hollow to the north (before 40 ka BP) and the Lago Enol (before 38 ka BP). These results support previous evidence that the maximum extent of southern European glaciers occurred earlier than in northern Europe. Alternation of homogeneous and laminated proglacial sediments during the glacier retreat illustrate a dynamic glacial evolution during the Marine Isotope Stage (MIS) 3 (40–26 ka BP). A slight warming is detected at 26 ka ago with the change from proglacial sediments (in a lake located in contact to the glacier) to glaciolacustrine sedimentation (in a non‐contact or distal lake). Finally, the onset of organic‐rich sediments took place at 18 ka ago. This last transition occurred in two phases, similarly to the North Atlantic Last Termination, suggesting a link between North Atlantic Deep Water formation oscillations and palaeohydrological variability in the Cantabrian Mountains. Copyright © 2009 John Wiley & Sons, Ltd.     

Estimation of seismic hazard parameters in TERESA test areas

A general overview of some of the problems involved in earthquake catalogue handling is given as part of the works carried out into the ESC/SC8-TERESA project related with the seismic hazard assessment in two selected test areas: Sannio-Matese in Italy and the northern Rhine region (BGN). Furthermore, the necessary input data to be used in the calculation of seismic hazard has been obtained, including earthquake source zones and their seismic hazard parameters.The importance is pointed out of detailed analysis of seismic catalogues, mainly in relation to the use of aftershock information, the historical records of the region, and the possible temporal and spatial variation of seismicity, which could have an important influence on short-term hazard assessment.     

Assessment of seismic hazard for the Sannio-Matese area of Southern Italy — A summary

The working group on Test Regions for Evaluation of Methods for Seismic Hazard Assessment in Europe (TERESA), consisted of 15 members from 10 different European countries. Methods and experience gathered in these countries have been compared and discussed for two test areas in Europe: the Sannio-Matese region, Southern Italy, with high seismic activity, and the border region between Belgium, The Netherlands, and Federal Republic of Germany, with low activity.This paper summarizes the results for one of the test areas, Sannio-Matese. Most of the participants used statistical procedures to assess earthquake hazard, receiving results in terms of probability of occurrence for intensity as the ground-motion parameter. It was found that careful preparation of input data and parameters is the major influencing factor, therefore most of the efforts of the working group was devoted to this task.The scatter of the obtained results of the group is considerable, mainly because of the uncertainties in the data and the subjectiveness involved in the procedures. For better control of both factors, more objective methods have to be developed.     

Seismic hazard computations for regions with low earthquake activity — A case study for the Belgium,The Netherlands and NW Germany area

The algorithms to evaluate seismic hazard, used and/or developed by five teams participating in the TERESA project, applied to the low seismicity area Belgium, The Netherlands and NW Germany are compared. The main differences in the results can be explained by the majority criterion of Egozcue et al. (1989), the differences in the upper bound and zonification and, in some cases, by a higher attenuation.     

Seismic activity related to the 1991 eruption of Colima Volcano,Mexico

Ten years after the last effusive eruption and at least 15 years of seismic quiescence, volcanic seismic activity started at Colima volcano on 14 February 1991, with a seismic crisis which reached counts of more than 100 per day and showed a diversity of earthquake types. Four other distinct seismic crises followed, before a mild effusive eruption in April 1991. The second crisis preceded the extrusion of an andesitic scoriaceous lava lobe, first reported on 1 March; during this crisis an interesting temporary concentration of seismic foci below the crater was observed shortly before the extrusion was detected. The third crisis was constituted by shallow seismicity, featuring possible mild degassing explosion-induced activity in the form of hiccups (episodes of simple wavelets that repeat with diminishing amplitude), and accompanied by increased fumarolic activity. The growth of the new lava dome was accompanied by changing seismicity. On 16 April during the fifth crisis which consisted of some relatively large, shallow, volcanic earthquakes and numerous avalanches of older dome material, part of the newly extruded dome, which had grown towards the edge of the old dome, collapsed, producing the largest avalanches and ash flows. Afterwards, block lava began to flow slowly along the SW flank of the volcano, generating frequent small incandescent avalanches. The seismicity associated with the stages of this eruptive activity shows some interesting features: most earthquake foci were located north of the summit, some of them relatively deep (7–11 km below the summit level), underneath the saddle between the Colima and the older Nevado volcanoes. An apparently seismic quiet region appears between 4 and 7 km below the summit level. In June, harmonic tremors were detected for the first time, but no changes in the eruptive activity could be correlated with them. After June, the seismicity decreasing trend was established, and the effusive activity stopped on September 1991.