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How Deforestation Impacts the Amazon River, Brazil – June 15th, 2013

0.4N 50.2W

June 15th, 2013 Category: Deforestation, Image of the day, Sediments MODISAqua

Brazil – June 15th, 2013

The Amazon Basin is the largest drainage basin in the world, covering over 7,049,947km2 of land, supplying the Amazon River with all of its water. The Amazon forest is an extremely important habitat containing 30.7% of the world’s rainforest and is the most species-rich biome in the entire world.

Deforestation has been a major problem in the Amazon since 1970s with the forest now 17.1% smaller than it originally was, which equates to 699,746km2 of forest lost. The Amazon has lost more forest than the total amount of forest India has, standing at around 440,000km2. The rate of deforestation has been and still is increasing every year.

The drastic amounts of deforestation obviously have a large impact, especially on the Amazon River itself, whose mouth is visible here. Forest cover anchors the soil, acting as a resistance to erosion, and when an area is cleared of forest erosion rates sky rocket. In a study done on the Ivory Coast a forested slope lost 0.03 hectares of soil per year, while a deforested slope lost up to 90 hectares per year, an increase of 3000%. All of this eroded sediment seeps into the river and is carried along its entire length to the delta on the east coast of Brazil.

An increase in sediment load has many adverse impacts: it can smother fish eggs, diminishing fish populations and hurting the ecosystem as well as the fishing industry, it can damage the infrastructure of a country by destroying bridges and dams which may hurt the economy, and it can increase flood rates and sizes by raising the river bed (click here for more information).

Deforestation in Brazilian State of Rondônia

11.5S 63.5W

June 14th, 2013 Category: Deforestation MODISTerra

Brazil – June 14th, 2013

The conversion of tropical rain forests to pasture and cropland is having dramatic effects on the environment. Particularly intense and rapid deforestation is taking place in the state of Rondônia, Brazil, part of which is shown here.

About 30% (3,562,800 km2) of the world’s tropical forests are in Brazil. The estimated average deforestation rate from 1978 to 1988 was 15,000 km2 per year. In Rondônia, 67,764 km2 of rain forest had been cleared through 2003.

Systematic cutting of forest vegetation starts along roads and then fans out to create the “feather” or “fishbone” pattern, which begins to show in the eastern half of the 1986 image. The deforested land and urban areas appear lavender; healthy vegetation appears green (click here for more information).

Sediment Loads of the Amazon River, Brazil

0.3N 49.9W

June 4th, 2013 Category: Rivers, Sediments MODISAqua

Brazil – June 4th, 2013

Sediment loads can be calculated by converting cosmogenic nuclide-derived rates using their sediment-producing areas. The fluctuations in the modern sediment loads of the Amazon River are due to the absence of long-term deposition within the basin and to the buffering capability of the large Amazon floodplain. The buffering capability dampens short-term, high-amplitude fluctuations (climatic variability in source areas and anthropogenic soil erosion) by the time the denudation rate signal of the hinterland is transmitted to the outlet of the basin (click here for more information).

Drought in the Amazon Delta Region and Effects on Global Warming – June 2nd, 2013

0.0N 51W

June 2nd, 2013 Category: Climate Change, Image of the day, Rivers, Sediments

Brazil – June 1st, 2013

An increased frequency of droughts in the Amazon, particularly the delta region (visible here), such as the ones that occurred in 2005 and 2010, threatens to turn the world’s largest tropical forest from a sponge that absorbs greenhouse gases into a source of them, causing accelerating global warming. This is because the trees normally absorbing carbon dioxide as they grow, helping to cool the planet, release these gases when they die and rot.

The 2010 drought caused a reduction of rainfall in an area of 3 million square kilometres of forest – far more than the 1.9 million square kilometres affected in 2005. Because of this, the Amazon forest will no longer absorb in 2010 and 2011 its usual volume of 1.5 billion tons of carbon dioxide from the atmosphere. Moreover, the dead and dying trees will release 5 billion tons of gas over the next year, causing the cumulative impact to reach 8 billion tons.

Emissions caused by the two droughts were probably sufficient to cancel all of the carbon absorbed by the Amazon forest in the last ten years. If such events occur more frequently, the Amazon forest would reach a point where, from a valuable store of carbon reducing the speed of climate change, it would change into a large source of greenhouse gases, which could accelerate global warming (click here for more information).

Fires in Mato Grosso, Brazil

12.9S 54.1W

May 21st, 2013 Category: Fires, Rivers

Brazil – May 21st, 2013

Plumes of smoke can be seen from fires in the state of Mato Grosso, in western Brazil. The two main fires, best observed in the full image, can be seen in the lower left and upper right quadrants, releasing smoke westward. Between the two fires is a tract of heavily forested land through which the Ronuro River flows.

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