The Colourful Chemistry of the Amazonian Rainforest

Author: Simon Moorhouse
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Date: Jul 15, 2015

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The first ever high-resolution chemical maps of the Amazon rainforest have been created, revealing a landscape that’s usually only visible as 50 shades of green as a thriving multicolour sprawl.

In a study authored by Greg Asner of the Carnegie Institute for Science, it was revealed that plants in different areas of the rainforest are arranged by shared chemical traits, related to the availability of resources such as water and nutrients, and the geography of carbon dioxide intake as determined by variations in soil and elevation.

The study was published in Nature Geoscience and is called “Landscape biogeochemistry reflected in shifting distributions of chemical traits in the Amazon forest canopy”.

Asner’s team used airborne laser-guided imaging spectroscopy to develop maps of 16 forest canopy traits across four large landscapes which, between them, demonstrate the three most common forest community types. It has enabled us, for the very first time, to literally view the Amazonian rainforest in a whole new light.

Asner said: “Our findings tell us that lowland Amazon forests are far more geographically sorted than we once thought.

“It is not simply a swath of green that occurs with everything strewn randomly. Place does matter, even if it all appears to be flat and green monotony at first glance.”

Covering five million square kilometres, the Amazonian rainforest contains thousands of species of trees and plants, all of which synthesise a range of chemicals to fulfil functions such as capturing sunlight, attracting pollinators, and repelling herbivores.

The above map is just one of the images produced and it demonstrates the relative abundance of growth chemicals. The red areas of the map are naturally packed with growth chemicals, while the neighbouring yellow and green terraces have fewer.

Never before have so many chemicals been measured and mapped in any forest ecosystem on Earth. With studies like this, we are better placed to understand our planet’s geographic patterning and vast biodiversity, which will help us attain a more thorough understanding of evolution and species’ future in a rapidly changing world.

Asner continued: “Looking at the lowland Amazon with this kind of detail you can see back in time, from the way the topography was shaped millions of years ago, which still affects soils and mineral availability today, to the way that different species evolved to take advantage of this great variety of subtly changing conditions.

“And we can peer into the future and see how quickly human activity is changing the kaleidoscope of diversity that has been uniquely shaped over millions of years.”

 

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