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Investigating mercury sources in the deep Critical Zone

Justin Richardson in Adventures in the Critical Zone

Jun 12, 2019

An illustrated introduction to Justin Richardson's research on mercury sources in the deep Critical Zone. 

By Justin Richardson

Illustrated by Alana McGillis.

Panel 1. We are introduced to Dr. Justin Richardson with shovel in hand in a deciduous forest of New England. Justin studies how metals move in the Critical Zone.

Panel 2. Justin is interested in metals because they are everywhere, rocks, rivers, and plants! Metals are essential for our bodies to function properly, but they can also be toxic, like lead, mercury, and arsenic.

Panel 3. The Critical Zone can act like a sponge and absorb metals from moving from to rivers and lakes. Mercury is shown being deposited at the top of a hill and moving down a hillslope towards a stream in the valley.

Panel 4. We know that the top layers of soils are important for holding onto metals like mercury, but Justin wondered if rock and weathered rock can store mercury from the atmosphere.

Panel 5. To test this idea, Justin collected drill core samples from deep (as deep as 40 feet) in the ground, where people generally do not think they are connected directly to the atmosphere. A drill rig is shown coring down deep in the CZ into the bedrock.

Panel 6. Justin’s project showed that the Critical Zone formed from weathered igneous rocks that can store mercury while sedimentary rocks can release mercury.

Panel 7. Studying metals in the deep Critical Zone was made possible by a team of scientists and they look forward to exploring more metals deep in the soils and weathered rock.

Justin B. Richardson

CZO INVESTIGATOR, STAFF. National Office outreach officer, Former CZO Post-Doctoral Fellow. Specialty: Soil biogeochemistry of plant-essential and toxic metals.

CZO Profile | Personal Website

Geochemistry / Mineralogy   EDUCATION/OUTREACH  

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Justin Richardson and his guests answer questions about the Critical Zone, synthesize CZ research, and meet folks working at the CZ observatories

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General Disclaimer: Any opinions, findings, conclusions or recommendations presented in the above blog post are only those of the blog author and do not necessarily reflect the views of the U.S. CZO National Program or the National Science Foundation. For official information about NSF, visit

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