Oil spill in South Atlantic (Brazil): Environmental and governmental disaster

Extreme weather impacts on tropical mangrove forests in the Eastern Brazil Marine Ecoregion.

Coastal wetlands are large reservoirs of soil carbon (C). However, the annual C accumulation rates contributing to the C storage in these systems have yet to be spatially estimated on a large scale. We synthesized C accumulation rate (CAR) in tidal wetlands of the conterminous United States (US), upscaled the CAR to national scale, and predicted trends based on climate change scenarios. Here, we show that the mean CAR is 161.8 ± 6 g Cm−2 yr−1, and the conterminous US tidal wetlands sequestrate 4.2–5.0 Tg C yr−1. Relative sea level rise (RSLR) largely regulates the CAR. The tidal wetland CAR is projected to increase in this century and continue their C sequestration capacity in all climate change scenarios, suggesting a strong resilience to sea level rise. These results serve as a baseline assessment of C accumulation in tidal wetlands of US, and indicate a significant C sink throughout this century. It remains challenging to estimate carbon accumulation rates in tidal wetlands on a scale as large as the conterminous US. Here, the authors find that mean C accumulation rates vary greatly among watershed regions but not among vegetation types, and that tidal wetlands’ C sequestration capability will remain or increase by 2100, suggesting a resilience to sea level rise.

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Tidal wetland resilience to sea level rise increases their carbon sequestration capacity in United States.

https://krishi.icar.gov.in/jspui/bitstream/123456789/36822/1/h5.pdf

Bioremoval of trace metals from rhizosediment by mangrove plants in Indian Sundarban Wetland

Brazilian mangroves extend from 4°30′N to 28°30′S, varying greatly in growth form, species distribution patterns, and stand structure, in spite of a limited floristic diversity. We divided the Brazilian coastline into eight units, within which physiographic and climatic conditions are relatively uniform, and described mangrove occurrence, species distribution and structural attributes characteristic of each segment. In general, greates mangrove coverage and greatest forest stature are found in areas with a large surplus of rainfall over potential evapotranspiration and macrotidal regimes. An exception was the segment containing the mouth of the Amazon river, where freshwater systems dominate over brackish or marine associations. We believe that the variability in species associations and the dominance of each in a given environment is predominantly determined by the characteristics of the landforms that can be colonized by each species in a given region. The type, size, and frequency of occurrence of available landforms is a function of the particular mix of fluvial, tidal, and wave energies found in a region. Different species colonize these sites depending on their adaptations and edaphic preferences. Climate affects mangrove colonization and growth. We suggest that Brazilian mangroves play a minor role in modifying the geomorphic setting; the spatial arrangement of the various forest types is a response to the underlying topography and edaphic conditions, and to the constraints imposed by climatic and hydrologic factors. The spatial arrangement of species does not necessarily show successional processes, but may be the result of direct and differential colonization on appropriate substrates.

Variability of mangrove ecosystems along the brazilian coast

Esta e uma sintese enquadrada na Rede de Monitoramento de Habitats Bentonicos Costeiros (ReBentos, GT4: Manguezais e Marismas), embasada em literatura cientifica que examina interacoes entre clima e biodiversidade, assim como fatores antropicos, incluindo aqueles responsaveis pela diminuicao da resiliencia sistemica. O objetivo deste trabalho e determinar as dificuldades quanto a deteccao de sinais precoces e alertas de mudancas climaticas com dados de monitoramento. No presente trabalho, tambem foram exploradas formas de contornar os diversos obstaculos identificados. A exposicao e a sensitividade de especies de mangue e de marisma, bem como dos ecossistemas dos quais fazem parte, os tornam extremamente vulneraveis e potenciais indicadores ambientais de mudancas de nivel do mar e outras respostas as variacoes do clima. Entretanto, a interpretacao de mudancas em manguezais e marismas e em seus atributos sistemicos deve ser meticulosa, considerando assinatura energetica, regime de disturbios e pressoes ambientais em cada local de estudo. Os potenciais de adaptacao e de sobrevivencia, em resposta a tais mudancas, dependem da fisiologia de cada especie e dos processos contextuais onde reside a resiliencia e a capacidade de persistir (em niveis local, de paisagem e regionais). A zona costeira deve ser alvo de medidas antecipatorias para reducao de riscos por quaisquer impactos, uma vez que nela ha intensa convergencia de processos sociais e ecologicos. Os ecossistemas dessa zona devem ser integrados em estrategias de adaptacao. O manejo costeiro deve ser embasado em mitigacao pro-ativa e colaborativa de longo-termo, sempre com base em estudos ecossistemicos e em programas de monitoramento que possam 1) prover sistema de alerta precoce; 2) preencher lacunas entre correlacoes simplistas que proveem inferencias fracas, e abordagens baseadas em processos que levem a atribuicoes mais confiaveis e a melhores niveis de antecipacao.

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Jussara Shirazawa-Freitas

Papers

Climate changes in mangrove forests and salt marshes