Amazon on EARTH Magazine

Aerosols help mitigate ill effects of Amazon fires

Mon, 21 Sep 2015 10:54:42 -0400

Taken by NASA's Aqua satellite, this image shows deforested areas and active forest fires (red dots) in the Brazilian state of Mato Grosso on Aug. 12, 2007. Credit: NASA Earth Observatory/Jesse Allen.

Forest fires across the Amazon Basin — many of which are set intentionally to clear land for human use — burn thousands of square kilometers each year, releasing roughly 240 billion kilograms of stored carbon to the atmosphere. According to a new study, however, the vast amounts of black carbon and other aerosolized particles also sent into the skies by such fires offset much of this carbon loss by stimulating increased photosynthesis.

Sediment load shapes rivers

Tue, 16 Jun 2015 11:43:57 -0400

Meanders of the Rio Beni in Bolivia. Credit: Landsat/U.S. Geological Survey.

The amount of sediment carried in meandering rivers influences how quickly the bends in those rivers migrate back and forth, according to recent research in Nature Geoscience addressing a longstanding question regarding river evolution. Meanders form when flowing water erodes one riverbank while simultaneously depositing sediment on the opposite bank, gradually creating more and more pronounced U-shaped bends. Sometimes, the rivers cut new channels across the narrow necks of such bends, isolating the abandoned meanders to form distinctive oxbow lakes.

No pre-Columbian deforestation of the western Amazon

Mon, 18 Jun 2012 18:47:37 -0400

Crystal McMichael (right) and undergraduate student Monica Zimmerman collect soil cores from the western Amazon. The cores indicate that pre-Columbian western Amazonian populations did not disturb the rainforests. Courtesy of Crystal McMichael

The team collected soil cores from deep in the forest as well as along rivers, such as here atop a river bluff overlooking the Madre de Dios River in the Peruvian Amazon. Courtesy of Benjamin McMichael

Deep in the western Amazon rainforest, Crystal McMichael tries not to swat at the sweat bees crawling on the back of her neck as she samples the soil beneath her.