Redwood Reader

Another glomalin source article in my collection to share. This one relates Kristi Nichols, Sara Wright and and E.Kudjo Dzantor, both USDA soil scientists working at ARS, quantifying glomalin rates and carbon storage. Rough numbers of 1-100 mg/g give us some theoretical numbers to look for when we begin measuring our own storage sites. I have written several scientists requesting information relating glomalin to forests. Only Sara Wright has responded, only saying she wished she could work in the redwoods.

Glomalin, the Unsung Hero of Carbon Storage
ARS News Service
Agricultural Research Service, USDA
Don Comis, (301) 504-1625, comis@ars.usda.gov
September 6, 2002

Glomalin, a recently discovered major component of soil organic matter,
stores about a third of the world's soil carbon, offsetting industrial
pollution. This is according to a recent collaborative study by scientists
with the Agricultural Research Service and the University of Maryland
(U-MD) at College Park. The study was partially funded by the U.S.
Department of Energy.

The study was done by Kristine A. Nichols, a U-MD soil science Ph.D.
candidate and technician at ARS' Sustainable Agricultural Systems
Laboratory in Beltsville, Md., along with colleagues Sara F. Wright and E.
Kudjo Dzantor. Wright, an ARS soil scientist, discovered glomalin in 1996,
and Dzantor is a U-MD soil scientist.

Glomalin is a sticky protein produced by root-dwelling fungi and sloughed
into soil as roots grow. By gluing soil particles and organic matter
together, it stabilizes soil and keeps carbon from escaping into the
atmosphere. In an earlier study, Wright found that glomalin serves as a
corrective to global warming because it increases with carbon dioxide
levels.

Nichols and colleagues detected large amounts of glomalin in soils from
four states, showing it to be a major part of organic matter. The glomalin
weighed 2 to 24 times as much as humic acid, which was previously thought
to store the most carbon. But Nichols found that humic acid only stored 8
percent of total soil carbon compared to glomalin's 27 percent.

Wright has found glomalin in soils from around the world, ranging in
weight from less than 1 milligram per gram (mg/g) of sample to more than
100 mg/g. She found the highest levels in Hawaiian and Japanese soils,
indicating that some soils might be able to store large amounts of carbon
in glomalin with a turnover rate of 7 to 42 years. She is on a team
investigating underground carbon storage in tropical forests, thought to
be major carbon reservoirs.

For more on glomalin, see the September 2002 issue of Agricultural
Research magazine, online at:
http://www.ars.usda.gov/is/AR/archive/sep02/soil0902.htm

ARS is the U.S. Department of Agriculture's chief scientific research
agency.