Distribution, sources and consequences of nutrients, persistent organic pollutants, metals and microplastics in South American estuaries.

The Samarco mine tailing disaster: A possible time-bomb for heavy metals contamination?

Multiscale land use impacts on water quality: Assessment, planning, and future perspectives in Brazil.

Mangroves of the semiarid Caatinga region of northeastern Brazil are being rapidly converted to shrimp pond aquaculture. To determine ecosystem carbon stocks and potential greenhouse gas emissions from this widespread land use, we measured carbon stocks of eight mangrove forests and three shrimp ponds in the Acarau and Jaguaribe watersheds in Ceara state, Brazil. The shrimp ponds were paired with adjacent intact mangroves to ascertain carbon losses and potential emissions from land conversion. The mean total ecosystem carbon stock of mangroves in this semiarid tropical landscape was 413 ± 94 Mg C/ha. There were highly significant differences in the ecosystem carbon stocks between the two sampled estuaries suggesting caution when extrapolating carbon stock across different estuaries even in the same landscape. Conversion of mangroves to shrimp ponds resulted in losses of 58%–82% of the ecosystem carbon stocks. The mean potential emissions arising from mangrove conversion to shrimp ponds was 1,390 Mg CO2e/ha. Carbon losses were largely from soils which accounted for 81% of the total emission. Losses from soils >100 cm in depth accounted for 33% of the total ecosystem carbon loss. Soil carbon losses from shrimp pond conversion are equivalent to about 182 years of soil carbon accumulation. Losses from mangrove conversion are about 10‐fold greater than emissions from conversion of upland tropical dry forest in the Brazilian Caatinga underscoring the potential value for their inclusion in climate change mitigation activities.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/ece3.4079

Shrimp ponds lead to massive loss of soil carbon and greenhouse gas emissions in northeastern Brazilian mangroves

In November 2015, the Doce River basin was struck with Brazil’s worst environmental disaster: the collapse of an iron ore mining waste water dam delivering about 60 Mm3 of contaminated mud that traveled from its headwaters to the Atlantic Ocean. We analyzed the impact of the tailings dam failure on the turbidity of the Doce River plume and coastal waters based on remote sensing methods applied to Landsat and MODIS-Aqua imagery. Turbidity maps were obtained using a semi-analytical algorithm that uses a two band (i.e., red and near infrared) selection scheme to optimize the retrieval for a wide range of turbidity levels. The dam failure occurred in the context of a severe hydrological drought, but despite the abnormally low streamflow the turbidity front of the Doce River plume at the coast peaked to levels above 1000 FNU after the disaster. With subsequent rainfall-runoff events, the deposited mud within the river-estuary system continued to be washed out and cause high turbidity levels with extensive plumes over the coastal zone. The high turbidity (>20 FNU) plume front reached 11 km off the coast towards the southern shelf, the moderate turbidity plume (10–20 FNU) reached 39 km, and the low turbidity plume (

Lucas Barreto Correa

Papers

The impacts of the Samarco mine tailing spill on the Rio Doce estuary, Eastern Brazil.

Mangrove clearing impacts on macrofaunal assemblages and benthic food webs in a tropical estuary.