*[Enwl-eng] Meet nature's firefighters
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Thu Jun 8 01:03:33 MSK 2023
+ fungi carbon storage underestimated
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A formidable ally in the fight against climate change is hidden under
our feet. New research suggests 36% of the carbon dioxide (CO₂) emitted from
burning fossil fuels each year is taken up by a group of fungi called
mycorrhizae, which live in partnership with plants in the soil.
All you're likely to see of these organisms is a mushroom protruding
from the earth. But underground, mycorrhizal fungi form threads called
filaments that connect the roots of most plants, exchanging water and
nutrients for sugars and fats made by photosynthesis.
The academics behind the new research believe scientists have
massively underestimated the role fungi play in keeping the man-made gases
driving climate change out of the atmosphere. And these fungi are in good
company: countless species are active participants in the carbon cycle, and
they need our help to ensure they can continue helping us.
You're reading the Imagine newsletter – a weekly synthesis of academic
insight on solutions to climate change, brought to you by The Conversation.
I'm Jack Marley, energy and environment editor. This week, we meet the
species working hard to slow global heating.
"On land, the natural carbon cycle involves a delicate balance. Plants
take CO₂ from the atmosphere through photosynthesis, while other organisms
emit it back into the atmosphere," say Adam Frew, Carlos Aguilar-Trigueros,
Jeff Powell and Natascha Weinberger, who study how plants and soil
microorganisms interact at Western Sydney University.
"Now we know the carbon transfer from plants to mycorrhizal fungi isn’t
a side note – it’s a substantial part of this equation."
Animals release some CO₂ when they exhale. But they can also help bury
carbon – and increase its duration in safe storage underground.
While most of the carbon stored in trees is decomposed and recycled to
the atmosphere as greenhouse gas in less than a century, the soil beneath
grasslands with few trees but lots of large plant-eaters, such as elephants,
can guard carbon for thousands – even tens of thousands – of years in
hard-to-reach underground pools.
So how do these animals do it? Jeppe Aagaard Kristensen, a visiting
postdoctoral fellow at the University of Oxford's Ecosystems Lab, says that
up to half of the plant matter eaten by elephants is excreted as dung or
urine. Decomposers like beetles and earthworms can break this down more
easily than dead leaves, for instance, since it's already been digested, and
the carbon contained within it then enters long-term storage in the soil.
"Large animals seem adept at reorganising where ecosystems store
carbon, directing a larger fraction towards persistent and stable reservoirs
underground," says Kristensen.
"This shows how valuable intact wildlife communities can be, and
should urge us to protect the few remaining herbivore-rich ecosystems on
Earth, such as the African savanna."
And it's not just herbivores: a recent study showed how a 50-year
campaign to restore tiger populations in India had unexpected benefits for
the climate.
Project Tiger established nine tiger reserves in 1973. Today, 54 such
areas exist across India – that's 75,000 sq kilometres of jungle, mangrove
swamp and dry forest which equates to 2% of the country.
"These habitats might seem very different, but the common link is of
course lots of trees," says Simon Evans, a principal lecturer in ecotourism
at Anglia Ruskin University.
The strict protection afforded to tigers within this network of
reserves prevented deforestation – and may have kept 1 million tonnes of CO₂
out of the atmosphere as a result between 2007 and 2020.
Some species, such as the African forest elephant, can even increase
the capacity of forests to store carbon. A typical three-tonne female must
eat roughly 200kg of bark and leaves daily. Saplings are particularly
popular as they have fewer of the chemical defences which make older trees
in a tropical forest difficult or unpleasant to eat. By weeding out the
small, fast-growing vegetation, elephants promote larger, woodier trees
which lock up more carbon.
"The authors estimate that the disappearance of African forest
elephants would result in a loss of as much as 7% of the carbon stocks in
Central African forests", Evans says.
It's important to not get carried away, however. You may have heard
that whales are good at drawing carbon down from the air and into the deep
sea, for example.
"Their plumes of poo contain so many nutrients that phytoplankton
blooms can form in a whale's wake. These tiny photosynthesising creatures
soak up carbon dioxide in their bodies. When they die, they can sink to the
bottom and be covered in sediment, storing the carbon," explains Olaf
Meynecke, a research fellow in marine science at Griffith University.
However, Meynecke's research suggests that whales are likely to only
make a limited contribution to carbon storage. Of the 53 billion tonnes of
carbon absorbed by the oceans annually (mainly as a result of
photosynthesising algae), 4 billion tonnes sink below the surface and only
1% of that is stored in sea-floor sediment for the long term.
Not enough is known about the climate benefits of whale conservation.
Trumpeting its usefulness could distract from proven solutions such as
preventing the burning of fossil fuels, Meynecke says.
Even so, understanding how large wild animals in particular mitigate
climate change exposes important connections between the multiple aspects of
the ecological crisis, according to Heather Alberro, a lecturer in global
sustainable development at Nottingham Trent University.
Alberro highlights how the captive rearing of animals for meat and
dairy is one of the largest contributors to climate change. In contrast,
animals that are allowed to embed themselves in natural cycles can help
return carbon to long-term storage.
"Robin Wall Kimmerer, environmental scientist and citizen of the
Potawatomi Nation, refers to the 'honourable harvest'. When deciding
anything -- from how and where to build homes to how to produce food and
source energy -- principles to live by include taking only what we need,
always leaving some for others, and sustaining those who sustain us."
- Jack Marley, Environment commissioning editor
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Imagine.
Hidden carbon: Fungi and their ‘necromass’ absorb one-third of the
carbon emitted by burning fossil fuels every year
New research about underground fungal filaments suggests these
networks store a vast amount of carbon. All the more reason to preserve
them.
Read more
Climate change: how elephants help pump planet-warming carbon
underground
Efforts to preserve biodiversity and slow climate change make natural
bedfellows.
Read more
Tiger protection in India also saved 1 million tonnes of carbon
emissions – new study
Deforestation rates are lower in tiger reserves.
Read more
Forest elephants are our allies in the fight against climate change,
finds research
A new study shows these elephants boost the carbon stored in their
forests by 7%.
Read more
Whale of a tale? The stories about whales helping tackle climate
change are overblown
We want good news on climate change. But whales storing enough carbon
needs more evidence.
Read more
Grand National protests: Animal Rising campaigners reveal how
exploiting animals harms us too
The horse race was disrupted by activists from the Extinction
Rebellion offshoot.
Read more
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From: Imagine newsletter
Sent: Wednesday, June 07, 2023 8:02 PM
Subject: Meet nature's firefighters
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