Variability in nearshore fish biodiversity indicators after a mining disaster in eastern Brazil.

The rupture of the Fundão mining dam (Doce river basin, Brazil) caused a wide range of negative impacts. Yet, assemblage-level implications to estuarine and coastal fishes remain unclear, partly due to the lack of pre-disaster information. Based on monthly otter trawl surveys, we analyzed spatial and seasonal variability in univariate (total biomass, biomass of species vulnerable to exploitation, rarefied richness and evenness) and multivariate (species composition and trophic composition) indicators of fish biodiversity in the Doce river delta, eastern Brazil.

Effects of seasonal contaminant remobilization on the community trophic dynamics in a Brazilian tropical estuary.

In tropical estuaries, wet seasons are responsible for the downstream transport of allochthonous material from the upper basin and flooded plains. Although allochthonous matter is commonly associated to nutrient and detritus input, pollutants are also transported throughout the basin or suspended from the river bottom via strong streamflow remobilization and rainfall dynamics. We assessed community and population trophic niche-based patterns using organisms' stable isotopes signatures in the wet and the dry seasons to test if estuarine trophic diversity is affected by remobilization of metal-contaminated material from a mining dam collapse that occurred in the Doce river basin, Brazil.

Early evidences of niche shifts in estuarine fishes following one of the world's largest mining dam disasters.

The Fundão dam collapse occurred on November 2015 in Mariana city (Brazil), provoking a series of ecological impacts over the Doce river basin and its nearshore environment. However many impacts over fishery target fauna (fish and shrimp) are still unknown or underestimated due to the lack of baseline data in the region. In the present study we assessed the isotopic niches modeled from δC and δN signatures of six estuarine fish species before and after the impact to assign potential shifts at the population- and community-level.