1. Although 20% of Brazilian territory is covered by wetlands, wetland inventories are still incomplete. In 1993, Brazil signed the Ramsar Convention but a coherent national policy for the sustainable management and protection of wetlands has yet to be established. 2. Major gaps in the definition of a specific wetland policy are twofold: (1) the lack of standardized criteria by which wetlands are defined and delineated that reflects the specific ecological conditions of the country and (2) the lack of a national classification of wetlands that takes into account specific hydrological conditions and respective plant communities. 3. In recent years, efforts have been made at a regional level to improve public awareness of the ecology of Brazilian wetlands, their benefits to society, and the major threats endangering them. Studies have shown that wetlands play a crucial role in the regional hydrological cycle and provide multiple benefits for local populations. Furthermore, Brazilian wetlands contribute significantly to South American biodiversity. Therefore, wetland conservation and sustainable management should be given high legislative priority. 4. This article provides a synthesis of the current body of knowledge on the distribution, hydrology, and vegetation cover of Brazilian wetlands. Their definition, delineation, and classification at the national level are proposed in order to establish a scientific basis for discussions on a national wetland policy that mandates the sustainable management of Brazil’s extremely diverse and complex wetlands. This goal is particularly urgent in the face of the continuing and dramatic deterioration of wetlands resulting from large-scale agro-industrial expansion, and hydroelectric projects as well as the projected impact of global climate change on hydrological cycles

Library of Congress Cataloging-in-Publication Data Lacerda, Luiz Drude de. Mercury from gold and silver mining : a chemical time bomb? 1 Luiz Drude de Lacerda, Wim Salomons. p. cm.-(Environmental science) Includes bibliographical references and index. 1. Mercury-Environmental aspects. 2. Gold mines and mining-Environmental aspects. 3• Silver mines and mining-Environmental aspects. 4• Mercury wastes -Environmental aspects-Tropics.

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The contribution of the Deccan Traps (west-central India) volcanism in the Cretaceous-Paleogene (KPg) crisis is still a matter of debate. Recent U-Pb dating of zircons interbedded within the Deccan lava flows indicate that the main eruptive phase (>1.1 × 10 6 km 3 of basalts) initiated ~250 k.y. before and ended ~500 k.y. after the KPg boundary. However, the global geochemical effects of Deccan volcanism in the marine sedimentary record are still poorly resolved. Here we investigate the mercury (Hg) content of the Bidart (France) section, where an interval of low magnetic susceptibility (MS) located just below the KPg boundary was hypothesized to result from paleoenvironmental perturbations linked to the paroxysmal Deccan phase 2. Results show Hg concentrations >2 orders of magnitude higher from ~80 cm below to ~50 cm above the KPg boundary (maximum 46.6 ppb) and coincident with the low MS interval. Increase in Hg contents shows no correlation with clay or total organic carbon contents, suggesting that the Hg anomalies resulted from higher input of atmospheric Hg species into the marine realm, rather than organic matter scavenging and/or increased runoff. The Hg anomalies correlate with high shell fragmentation and dissolution effects in planktic foraminifera, suggesting correlative changes in marine biodiversity. This discovery represents an unprecedented piece of evidence of the nature and importance of the Deccan-related environmental changes at the onset of the KPg mass extinction.

Mangroves function as a natural coastline protection for erosion and inundation, providing important environmental services. Due to their geographical distribution at the continent-ocean interface, the mangrove habitat may suffer heavy impacts from global climate change, maximized by local human activities occurring in a given coastal region. This review analyzed the literature published over the last 25 years, on the documented response of mangroves to environmental change caused by global climate change, taking into consideration 104 case studies and predictive modeling, worldwide. Most studies appeared after the year 2000, as a response to the 1997 IPCC report. Although many reports showed that the world's mangrove area is decreasing due to direct anthropogenic pressure, several others, however, showed that in a variety of habitats mangroves are expanding as a response to global climate change. Worldwide, pole ward migration is extending the latitudinal limits of mangroves due to warmer winters and decreasing the frequency of extreme low temperatures, whereas in low-lying coastal plains, mangroves are migrating landward due to sea level rise, as demonstrated for the NE Brazilian coast. Taking into consideration climate change alone, mangroves in most areas will display a positive response. In some areas however, such as low-lying oceanic islands, such as in the Pacific and the Caribbean, and constrained coastlines, such as the SE Brazilian coast, mangroves will most probably not survive.