permaculture

[Lawrence London <lfljvenaura@gmail.com>]

https://phys.org/news/2013-03-fungi-responsible-carbon-sequestration-northern.html?fbclid=IwAR2e2Fyo1MCnK-5YCjlGqq5qNc-BLUqiwby17z7x4-Jn0yKTd-MUYKKJR00#inlRlv

Study finds fungi, not plant matter, responsible for most carbon
sequestration in northern forests March 29, 2013 by Bob Yirka, Phys.org
report <https://phys.org/weblog/>
[image: Study finds fungi, not plant matter, responsible for most carbon
sequestration in northern forests]
<https://3c1703fe8d.site.internapcdn.net/newman/gfx/news/hires/2013/dfgtghtr.jpg>
The study system consists of 30 islands of different sizes in the two large
lakes, Lake Uddjaure and Lake Hornavan, near Arjeplog in northern Sweden.
Credit: Karina Clemmensen (Phys.org) —A new study undertaken by a diverse
group of scientists in Sweden has found that contrary to popular belief,
most of the carbon that is sequestered in northern boreal forests comes
about due to fungi that live on and in tree roots, rather than via dead
needles, moss and leaf matter. In their paper published in the journal
*Science*, the team describes their findings after taking soil samples from
30 islands in two lakes in northern Sweden.

Scientists have known for quite some time that northern forests sequester a
lot of carbon—they pull in carbon dioxide after all, and "breath" out
oxygen. But what the trees actually do with the carbon has been a matter of
debate—most have suggested that it's likely carried to needles and leaves
then eventually drops to the forest floor where over time decomposition
causes it to leech into the soil. If that were the case, this new team of
researchers reasoned, then the newest carbon deposits
<https://phys.org/tags/carbon+deposits/> should appear closest to the
surface of the forest floor <https://phys.org/tags/forest+floor/>. But this
is not what they found—instead they discovered that newer deposits were
more likely to be found at deeper levels in the soil. This was because,
they learned, the trees were carrying much of the carbon they pulled in
down to their roots (via sugars) where it was being sequestered by a type
of fungi (*ectomycorrhizal*, aka mycorrhizal fungi
<https://phys.org/tags/mycorrhizal+fungi/>) that eats the sugars and expels
the residue into the soil.
[image: Study finds fungi, not plant matter, responsible for most carbon
sequestration in northern forests]
<https://3c1703fe8d.site.internapcdn.net/newman/gfx/news/hires/2013/dhfghgy.jpg>
Cortinarius armillatus forms mycorrhizal symbiosis with roots of birch
trees. Credit: Karina Clemmensen

In their study they found that 47 percent of soil carbon
<https://phys.org/tags/soil+carbon/> found on large island samples came
about due to fungi, as did a whopping 70 percent of carbon in small island 
soil
samples <https://phys.org/tags/soil+samples/>. Thus far, the team is only
able to guess why there are such differences in the soils, but theorize
it's likely due to differences in decomposition rates.

The amount of carbon stored in northern forests and how, is important
because such trees cover approximately 11 percent of the Earth's surface
and recent research has calculated that they hold approximately 16 percent
of all worldwide sequestered carbon. And that's important, of course,
because as global warming occurs, more sequestered carbon is released due
to faster decomposition rates of dead forest matter. What's still not
clear, however, is whether an increase in new forest growth due to warmer
temperatures in more northern areas is likely to offset the increase in
release of the sequestered carbon.

<https://phys.org/news/2013-03-fungi-responsible-carbon-sequestration-northern.html?fbclid=IwAR2e2Fyo1MCnK-5YCjlGqq5qNc-BLUqiwby17z7x4-Jn0yKTd-MUYKKJR00#>
*Explore
further:* Increased tropical forest growth could release carbon from the
soil <https://phys.org/news/2011-08-tropical-forest-growth-carbon-soil.html>

*More information:* Roots and Associated Fungi Drive Long-Term *Carbon*
Sequestration in Boreal Forest, *Science* 29 March 2013: Vol. 339 no. 6127
pp. 1615-1618 DOI: 10.1126/science.1231923
<http://dx.doi.org/10.1126/science.1231923>

*Abstract*
Boreal forest soils function as a terrestrial net sink in the global carbon
cycle. The prevailing dogma has focused on aboveground plant litter as a
principal source of soil organic matter. Using 14C bomb-carbon modeling, we
show that 50 to 70% of stored carbon in a chronosequence of boreal forested
islands derives from roots and root-associated microorganisms. Fungal
biomarkers indicate impaired degradation and preservation of fungal
residues in late successional forests. Furthermore, 454 pyrosequencing of
molecular barcodes, in conjunction with stable isotope analyses, highlights
root-associated fungi as important regulators of ecosystem carbon dynamics.
Our results suggest an alternative mechanism for the accumulation of
organic matter in boreal forests during succession in the long-term absence
of disturbance.


Read more at:
https://phys.org/news/2013-03-fungi-responsible-carbon-sequestration-northern.html#jCp