Rain drain

Rain drain

Note: Ca2+-calcium ion, K1+-potassium ion, Mg2+-magnesium ion, H+-hydrogen ion, H2SO4-sulphuric acid, HNo3-nitric acid; Black arrow-precipitation derived nutrients, Red arrow-rock derived nutrients
Source: University of California (www.info.ucr.edu/cgi_bin/display.cgi) as viewed on July 22, 2002

acid rain leaches essential metal nutrients such as potassium, calcium and magnesium from the top soil, posing a far graver threat to forests than previously estimated. This was discovered by Martin Kennedy, a scientist at the us-based University of California, and his colleagues.

The researchers experimented on trees in the unpolluted forests of southern Chile. "We went to the cleanest atmosphere on Earth so that we could find the closest thing to a long-term sustainable forest,' Kennedy said. "There, we sampled soils, stream water, rain and plants, and analysed the strontium isotope composition of each one.' Strontium isotopes indicate very accurately which fraction of nutrient comes from rain and which fraction comes from the rock. "We found that in the dominant tree species

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