Land-building marsh plants are champions of carbon capture
Wetlands are Earth's most efficient natural storage system for climate- warming carbon dioxide

Date:
May 5, 2022
Source:
Duke University
Summary:
Human activities such as marsh draining for agriculture are
increasingly eating away at saltwater and freshwater wetlands
that cover only 1% of Earth's surface but store more than 20%
of all carbon dioxide absorbed by ecosystems worldwide. A new
study shows that it's not too late to reverse the losses if
we use innovative restoration practices that replicate natural
landscape-building processes that enhance the restored wetlands'
carbon-storing potential.



FULL STORY ========================================================================== Human activities such as marsh draining for agriculture and logging
are increasingly eating away at saltwater and freshwater wetlands that
cover only 1% of Earth's surface but store more than 20% of all the climate-warming carbon dioxide absorbed by ecosystems worldwide.


==========================================================================
A new study published May 6 in Science by a team of Dutch, American and
German scientists shows that it's not too late to reverse the losses.

The key to success, the paper's authors say, is using innovative
restoration practices -- identified in the new paper -- that replicate
natural landscape- building processes and enhance the restored wetlands' carbon-storing potential.

And doing it on a large scale.

"About 1 percent of the world's wetlands are being lost each year to
pollution or marsh draining for agriculture, development and other
human activities," said Brian R. Silliman, Rachel Carson Distinguished Professor of Marine Conservation Biology at Duke University, who
coauthored the study.

"Once disturbed, these wetlands release enormous amounts of CO2from their soils, accounting for about 5 percent of global CO2emissions annually," Silliman said. "Hundreds, even thousands of years of stored carbon are
exposed to air and start to rapidly decompose and release greenhouse
gases. The result is an invisible reverse waterfall of CO2draining into
the atmosphere. The wetlands switch from being carbon sinks to sources."
"The good news is, we now know how to restore these wetlands at a scale
that was never before possible and in a way that both stops this release
of carbon and re-establishes the wetland's carbon storing capacity,"
he said.



==========================================================================
What makes most wetlands so effective at carbon storage is that they
are formed and held together by plants that grow close to each other,
Silliman explained.

Their dense above- and below-ground mats of stems and roots trap
nutrient-rich debris and defend the soil against erosion or drying out --
all of which helps the plants to grow better and the soil layer to build
up, locking in a lot more CO2 in the process.

In the case of raised peat bogs, the process works a little differently, Silliman noted. Layers of living peat moss on the surface act as sponges, holding enormous amounts of rainwater that sustain its own growth and
keeps a much thicker layer of dead peat moss below it permanently under
water. This prevents the lower layer of peat, which can measure up to
10 meters thick, from drying out, decomposing, and releasing its stored
carbon back into the atmosphere. As the living mosses gradually build up,
the amount of carbon stored below ground continually grows.

Successful restorations must replicate these processes, he said.

"More than half of all wetland restorations fail because the
landscape-forming properties of the plants are insufficiently taken
into account," said study coauthor Tjisse van der Heide of the Royal
Institute for Sea Research and the University of Groningen in the
Netherlands. Planting seedlings and plugs in orderly rows equidistant
from each other may seem logical, but it's counter- productive, he said.

"Restoration is much more successful when the plants are placed in large
dense clumps, when their landscape-forming properties are mimicked, or
simply when very large areas are restored in one go," van der Heide said.



========================================================================== "Following this guidance will allow us to restore lost wetlands at a much larger scale and increase the odds that they will thrive and continue
to store carbon and perform other vital ecosystem services for years
to come," Silliman said. "The plants win, the planet wins, we all win." Silliman and van der Heide conducted the new study with scientists from
the Netherlands' Royal Institute for Sea Research, Utrecht University,
Radboud University, the University of Groningen, the University of
Florida, Duke University, and Greifswald University.

By synthesizing data on carbon capture from recent scientific studies,
they found that oceans and forests hold the most CO2globally, followed
by wetlands.

"But when we looked at the amount of CO2 stored per square meter, it
turned out that wetlands store about five times more CO2 than forests and
as much as 500 times more than oceans," says Ralph Temmink, a researcher
at Utrecht University, who was first author on the study.

Funding for the new study came from the Dutch Research Council, the
Oak Foundation, Duke RESTORE, the Lenfest Ocean Program, the National
Science Foundation, and Natuurmonumenten.

In addition to his faculty appointment at Duke's Nicholas School,
Silliman is director of Duke RESTORE.


========================================================================== Story Source: Materials provided by Duke_University. Note: Content may
be edited for style and length.


========================================================================== Journal Reference:
1. Ralph J. M. Temmink, Leon P. M. Lamers, Christine Angelini,
Tjeerd J.

Bouma, Christian Fritz, Johan van de Koppel, Robin Lexmond,
Max Rietkerk, Brian R. Silliman, Hans Joosten, Tjisse van der
Heide. Recovering wetland biogeomorphic feedbacks to restore the
world's biotic carbon hotspots.

Science, 2022; 376 (6593) DOI: 10.1126/science.abn1479 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/05/220505180918.htm

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