Phosphorus and suspended matter retention in mangroves affected by shrimp farm effluents in NE Brazil

Mercury Sources, Emissions, Distribution and Bioavailability along an Estuarine Gradient under Semiarid Conditions in Northeast Brazil

In the semiarid coast of northeast Brazil, climate change and changes in land use in drainage basins affect river hydrodynamics and hydrochemistry, modifying the estuarine environment and its biogeochemistry and increasing the mobilization of mercury (Hg). This is particularly relevant to the largest semiarid-encroached basin of the region, the Jaguaribe River. Major Hg sources to the Jaguaribe estuary are solid waste disposal, sewage and shrimp farming, the latter emitting effluents directly into the estuary. Total annual emission reaches 300 kg. In that estuary, the distribution of Hg in sediment and suspended particulate matter decreases seaward, whereas dissolved Hg concentrations increase sharply seaward, suggesting higher mobilization at the marine-influenced, mangrove-dominated portion of the estuary, mostly in the dry season. Concentrations of Hg in rooted macrophytes respond to Hg concentrations in sediment, being higher in the fluvial endmember of the estuary, whereas in floating aquatic macrophytes, Hg concentrations followed dissolved Hg concentrations in water and were also higher in the dry season. Animals (fish and crustaceans) also showed higher concentrations and bioaccumulation in the marine-influenced portion of the estuary. The variability of Hg concentrations in plants and sediments agrees with continental sources of Hg. However, Hg fractionation in water and contents in the animals respond to higher Hg availability in the marine-dominated end of the estuary. The results suggest that the impact of anthropogenic sources on Hg bioavailability is modulated by regional and global environmental changes and results from a conjunction of biological, ecological and hydrological characteristics. Finally, increasing aridity due to global warming, observed in northeast Brazil, as well as in other semiarid littorals worldwide, in addition to increased water overuse, augment Hg bioavailability and environmental risk and exposure of the local biota and the tradition of human populations exploiting the estuary's biological resources.

Can Sustainable Development Save Mangroves?

The Earth is warming, ecosystems are being overexploited, oceans are being polluted, and thousands of species are going extinct—all fueled by the need for a permanent increase in production for more consumerism and development. “Business as usual” continues untouched, while increasing attention has been given to the “sustainable development” concept. Despite their importance as life supporting ecosystems, forests, oceans, and wetlands are being destroyed at an accelerating rate. The conservation and restoration of mangroves, for example, are also vital for the planet to face catastrophic global warming. Based on a non-systematic literature review, we address how true mangrove conservation is incompatible with so-called “sustainable development”. We turn to the urgent changes needed to avoid environmental and societal collapse, promoted by the Western economic development paradigm, and address why the sustainable development approach has failed to stop environmental degradation and protect resources for next generations. Proposed solutions involve the rejection of the capital-oriented, nature-predatory systems, degrowth, a deep transformation of our energy matrix, and a shift in our nutrition to lower levels of the food chain. These are based on a profound sense of responsibility over the planet, respecting all life forms, ecosystem dynamics, and life sustaining properties of the biosphere.