Brown rivers are 'more natural' (BBC)

[eppur_se_muova]

Rivers and lakes in northern Europe and North America that have turned brown are returning to a more natural, pre-industrialised state, a study says.

A major reduction in acid rain since the 1970s has resulted in more dissolved organic carbon entering the regions' waters, researchers suggest.

Writing in Nature, they say soils are becoming less acidic, resulting in more carbon being washed away by rainfall.

The staining has previously been linked to global warming and land-use change.

"The solubility of organic carbon is pH-dependent, so the more acidic a soil gets, the less soluble a number of these organic compounds are," explained co-author Don Monteith, from University College London, UK.
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more: http://news.bbc.co.uk/2/hi/science/nature/7104114.stm

[XemaSab]

1. This is confusing to me

It seems like the more acidic a soil gets, the more soluble the carbon would be.

My major reference for this is American spodosols. Maybe European soils are different. :shrug: