Lesson 32 Mineral Cycling - Alaska Geobotany Center

Calcium addition experiment
at Hubbard Brook
• In October 1999, calcium silicate - in a
mineral form known as "wollastonite" was
applied to all of Watershed 1 in an
experiment designed to replace the
calcium that has been washed out of the
soil by acid rain.
• A helicopter was used to apply forty-five
tons of wollastonite to the watershed,
increasing the levels of soil calcium to
those believed to exist before acid
precipitation began falling on the forest.
• Over the next 50 years (this is a VERY
long experiment!) scientists will
investigate the response of major
ecosystem processes, including stream,
soil, and soil water chemistry; forest floor
mass and chemistry; composition and
structure of the forest, aquatic ecology;
leaf chemistry; soil microorganism activity,
and ultimately tree growth
Courtesy of Hubbard Brook web page: www.hubbardbrook.org/education/SubjectPages/AcidRainPage.htm