The Amazon river is a major source of terrestrially derived organic carbon to the tropical Atlantic Ocean. Field, satellite and a vertically generalized production model data were used to estimate empirical surface salinity and fit an inverse logit function to investigate the limiting effect of salinity on the productivity in the Amazon river plume. Satellite data included Moderate Resolution Imaging Spectroradiometer, Soil Moisture and Ocean Salinity, and Aquarius missions. Previous empirical surface salinity models have relied on a very narrow range of salinity values and satellite data to estimate the spatial extent of the river plume. The empirical surface salinity model presented here extended the range of salinity values and captures all the main surface mesoscale features, particularly those related to the main path of the low‐salinity water. We also show that it is possible to gain new insights on the spatiotemporal variability of the Amazon river plume by improving the empirical surface salinity and expanding its sampling period with the aid of remote sensing data. The variability of primary productivity is dominated by the subannual (6 month) and annual (12 month) frequency bands. Low‐salinity river water influences surface primary productivity continuously during the year through mechanisms associated with the western tropical Atlantic circulation and vertical mixing.

The Amazon River low‐salinity plume takes part in important ocean and atmosphere processes that influence climate. In the last three decades, the intensification of the hydrological cycle has increased the interannual variability of total freshwater discharged into the ocean. However, the feedback mechanisms of the Amazon River plume acting on this intensification are not fully understood. Correlation maps and multiple regression analysis applied to 16 years of satellite data and river flow measurements indicate that a positive precipitation trend of 15 mm/year in the western Amazon basin follows the long‐term warming of the tropical Atlantic. This increased the total amount of freshwater discharged into the ocean and reduced the Amazon River plume salinity by 3.5% per year in the main plume water export pathway. Based on these results we propose a process‐oriented model of the feedback process that explains the intensification of the Amazon hydrological cycle.

O Programa Seguro-Desemprego do Pescador Artesanal, mais conhecido como Seguro Defeso, representa uma das mais importantes conquistas socioambientais dos pescadores artesanais no Brasil. O objetivo do artigo foi avaliar a evolução e distribuição dos recursos no estado do Pará. Foram utilizados dados disponíveis em publicações e nos sites do Instituto Brasileiro de Geografia e Estatística (IBGE), Controladoria Geral da União (CGU), Ministério do Trabalho e Emprego (MTE) e Ministério da Pesca e Aquicultura (MPA), abrangendo o período 2009-2013. Os resultados indicam crescimento significativo no número de beneficiários e volume dos recursos a partir de 2009. Os estados mais beneficiados localizam-se nas regiões Norte e Nordeste, onde o Pará ocupa a primeira colocação, seguido por Maranhão, Bahia, Amazonas e Piauí. No estado do Pará há concentração na concessão dos benefícios, pois 15 municípios responderam por 61,49% dos recursos aplicados no período analisado. O Programa é fundamental para garantir a sobrevivência dos pescadores durante o período do defeso e a sustentabilidade dos estoques pesqueiros, entretanto, é necessário um monitoramento mais efetivo, visando coibir fraudes na concessão dos recursos e garantir que ele cumpra o seu papel como instrumento de política socioambiental para pesca e aquicultura no Brasil e no estado do Pará.

No abstract

Abiotic and biotic factors are known drivers that modulate community assembly from a regional species pool. Recent evidence has highlighted the intrinsic role of phylogenetic history on communities' response to the environment. Understanding its exact role poses a challenge because community assembly is embedded in a spatio‐temporal context where dispersal capabilities and biotic interactions may also determine species niches, especially in isolated oceanic islands. We unravelled how reef fish abundances from four oceanic islands in the southwestern Atlantic responded to environmental variability through seven years considering their phylogenetic history, functional traits and species co‐occurrence patterns. Species response to environmental variation was assessed through a multivariate hierarchical generalized linear mixed model that allows the inclusion of spatio‐temporal random effects, fitted with Bayesian inference. We found a strong phylogenetic signal (0.98) and a relatively low variance in abundance explained by functional traits, from around 30% in spring to 33% in summer, based on a posterior probability > 0.9. The most important environmental factor was surface chlorophyll‐a concentration, a proxy for primary productivity, explaining up to 23% of abundance variance. The global spatial and temporal effects on abundance were also low, with a maximum of 18% for sampling sites in spring. Our study offers a synthesis of the influence of complex phylogenetic history and geographical isolation on reef fish species niches in isolated oceanic islands, gaining new insights into how assembly processes have shaped these isolated communities.