Mercury monitoring: Mercury stability in bird feathers

The influence of ultraviolet light, heating, freezing and weathering on the mercury concentration in the primary feathers from Guillemot and Black Guillemot has been examined. Even within 8 months of exposure variation in mercury concentration due to either loss of mercury or weight loss of the feathers has been found to be less than 10% relative.     

Certified discourse? The politics of developing soy certification standards

Certification systems are an increasingly prominent feature of privatized, market-based environmental governance. While the potential of such systems to effectively lead to sustainable outcomes continues to be of concern to researchers, a growing body of literature focuses instead on the ways in which certification systems embody politics and reflect existing power relations. This paper contributes to this literature by analyzing the processes involved in developing production standards for the certification of ‘responsible’ soy, within the emergent certification system initiated by the Roundtable on Responsible Soy (RTRS). The Discourse Coalition Framework (DCF), highlights several aspects of the RTRS that illustrate how the process of developing standards for responsible soy has been highly contested and has featured political struggles. First, broad discourse, rather than specific technical knowledge, is the basis for cohesion of different stakeholders within the RTRS. Secondly, opponents have effectively challenged the RTRS at the level of broad discourse (as opposed to specific technical criteria), but the challenge has curtailed possibilities for widespread participation in the RTRS. Thirdly, the broad discourse of responsible soy has enabled unlikely alliances that have consolidated power with profoundly political effects. These findings provide an alternative basis for critically analyzing certification systems, beyond outcome effectiveness.     

Montagne Pelée volcano (Martinique,in the French Lesser Antilles) hydrogeological system revealed by high-resolution helicopter-borne electromagnetic imagery

Montagne Pelée, on the French island of Martinique, eastern Caribbean Sea, has been one of the deadliest volcanoes in the world, with 30,000 victims following the 1902 eruption. Thousands of people still live nearby, and this volcano is a strategic “water tank” for Martinique Island, providing 40% of the island’s water supply. This research aimed to better understand its hydrogeological functioning and the relationship with its complex volcanological evolution, taking advantage of a high-resolution helicopter-borne geophysical survey correlated with hydrogeological data from the boreholes and springs databases. Electromagnetic data, correlated with hydrogeological data, allowed for the identification of unsaturated zones, aquifers, and seawater intrusions, as well as the main geological units. In addition, data synthesised from pumping tests revealed that the older the unconsolidated pyroclastic deposits, the lower their hydraulic conductivity. The structural asymmetry between the northeastern and southwestern volcano flanks impacts its hydrogeological functioning. Consequently, the Montagne Pelée hydrogeological conceptual model is marked by several distinguishable aquifers. The upper perched aquifer within recent lava domes is directly involved in, and impacted by, phreatic eruptions, and it supports low flowrate springs. The remaining effective rainfall infiltrates to depth and recharges the hydrothermal system through vertical fractures. The other aquifers are categorized into three groups: northeastern, southeastern and southwestern flank aquifers. This research is a new step toward a better understanding of the Lesser Antilles volcanoes and more broadly of the central and proximal parts of the andesitic active volcanoes.

     

Heat flow of the eastern Canadian rifted continental margin revisited

Continental shelves are regions where heat flow is not measured directly by conventional marine techniques, but estimated from oil exploration data with possible bias. In order to overcome this problem, we recently proposed a method based on neural networks (Geophys J Int 2006, 166 :115) that provides better constraints on thermal conductivity: it allowed us to derive 161 heat flow estimates on the eastern margin of Canada, where previous studies had concluded to the existence of heat flow higher than that in the adjacent continent and ocean. We conversely found rather homogeneous values (∼45–55 mW m⁻²) all along and across the margins, from Labrador to Nova Scotia. The difference seems essentially related to the porosity of sediments that was not taken into account in previous studies. Our results support a high asymmetry for the conjugate Iberian‐Canadian margins, and could indicate that mantle heat flow increases abruptly from the Canadian shield to the margins.     

Variation in mercury content of Guillemot feathers over 150 years

The feathers of 277 Black, Common and Brünnich's Guillemot from the Baltic, Kattegat, Faroe Islands and Greenland were analysed for mercury. The levels were found to be higher in the Baltic and the Kattegat compared to the Faroe Islands and Greenland. While the levels were almost constant for the last two areas a substantial increase during this century was found for the Baltic and the Kattegat. In Common Guillemots from the Baltic a decrease was indicated after 1969. In general the mercury levels were higher for Black Guillemots living close to the coast compared to the Uria sp. living off-shore. The inhomogeniety of the mercury load near the shore was indicated by a large individual variation within a colony of Black Guillemots. This variation was reinforced by differences in migration and feeding habits. It has been shown by analysis of individuals recaptured during successive years that the year to year variation of one individual is considerably smaller.It is concluded that chronological series based on feathers from sea birds and museum collections may contribute to the elucidation of the long term trend of mercury pollution at sea.