How Microbiomes Can Help Us Deal with Climate Change
microbes
are everywhere they live in the air the
ocean
the soil and on our bodies lots of them
but before you reach for the hand
sanitizer take a look
at these beautiful bacterial mats in
yellowstone’s grand prismatic spring
they’re absolutely amazing because
they’ve somehow figured out how to grow
happily
at near boiling temperatures ever since
life on earth began
probably in a place like this microbes
have kept planetary chemical cycles in
balance
today humans are altering that balance
and changing the climate
by emitting greenhouse gases into the
atmosphere but microbes might be able to
help us with our climate problem after
all
microbes are earth’s original and most
adaptable inhabitants
now i know that not everyone is so
enamored with microbes
my biology students tell me that they
usually think of pathogen when they hear
the word microbe
and i know we’re in the middle of a
global viral pandemic
but you should keep in mind that far
less than one percent of microbial
diversity
is actually pathogenic to humans in fact
most of the microbes we encounter are
beneficial
there are trillions of bacteria fungi
and viruses living
in and on us right now more of them than
human cells in the body
they help us digest our food protect us
from disease
and maybe even choose our mates
microbiologists call this assemblage of
tiny interlopers
the human microbiome we now know
that there are microbiomes in basically
every environment
in the same way that they help our human
bodies stay healthy
microbiomes in water soil and air are
critical for planetary health
for example cyanobacteria in the ocean
carry out photosynthesis and provide a
large fraction of the planet’s
breathable oxygen
even though they’re tiny their green
color can be seen from outer space
with satellites they may be harder to
see
but microbiomes in the soil are just as
important as the human or ocean
microbiome
i think about soil as a skin for the
planet that provides nutrients to
sustain crops and other plants
as an ecologist and climate scientist
i’ve been studying the microbes that
live in soil for 20 years now
just like we’ve seen with the human
microbiome cutting edge techniques in
molecular biology
especially dna sequencing show that soil
microbiomes are extremely diverse in
their genes
and life cycles scientists are starting
to figure
out how we can harness the diversity of
these often invisible
organisms to solve global problems like
climate change and food insecurity
take agricultural crops for example with
climate change causing more frequent
heat waves and droughts
crop plants may become stressed reducing
yields and threatening food security
but microbes can help there are
symbiotic
fungi called mycorrhizae that grow out
from plant roots
and into the soil where they collect
water and nutrients
then the plant and its symbiotic fungus
make a trade
the fungus sends water and nutrients
into the plant roots
and the plant pays back the fungus with
sugars from photosynthesis
to reduce stress on plants from climate
change farmers can inoculate the soil
with these beneficial fungi
land managers are also starting to use
the same approach
to help native plants recolonize
degraded soil during habitat restoration
so the next time you support an
environmental cause
maybe through a non-profit donation or
volunteer work remember
soil microbes need conservation too
the planet also relies on soil
microbiomes for other essential services
have you ever thought about what happens
to living things like these leaves
mosses and mushrooms when they die i’m
not talking about an existential crisis
i’m talking about microbial
decomposition
think about it like a type of biological
recycling practiced by very diligent
microbes
they take dead bodies and turn them into
useful nutrients
without this essential service life on
earth would grind
to a halt because dead stuff would pile
up depriving the next generation of life
forms
of the raw materials needed for growth
hundreds of researchers funded by the us
department of energy
are even trying to figure out how to
co-opt microbial decomposition
to produce sustainable biofuels from
wood grasses and other plant materials
fuels derived from plants and microbes
are part of the climate solution
because they don’t rely on fossil carbon
sources like coal and oil
at the same time ecologists like me are
very concerned about how climate change
might affect microbial recycling in the
environment
a warming climate might speed up the
process and release more greenhouse
gases into the atmosphere
a drier climate might slow down the
microbes and leave plants starved for
essential nutrients
fortunately there is reason for hope
microbes are
super adaptable because they can evolve
very quickly
for example you may have heard of
pathogenic bacteria like staph
evolving antibiotic resistance of course
that’s bad for us
but the same evolutionary process could
also help microbes adapt to
climate change which is good after all
microbes evolved
long ago to survive extreme conditions
like the hot springs of yellowstone
just like our human cells each microbial
cell contains a genome
and just like our genomes microbial
genomes contain
genes or dna sequences with instructions
for growth and survival
my colleagues and i have identified
genes that allow bacteria and fungi to
survive drought
and decompose dead plant material we’re
currently doing experiments to see how
fast these genes evolve
and what kinds of genetic changes make
bacteria and fungi
more resistant to drought some of our
prior research
shows that microbes have the potential
to deal with climate change
microbiomes and the services they
provide could cope not just by evolving
but also by shifting around the dominant
species of microbes
microbiomes are so diverse that even if
some of the species die out with climate
change
others might survive and take their
place allowing nature’s recycling to
continue
to test this idea my colleagues and i
designed special cages to contain
microbiomes from different habitats in
southern california
we sampled microbiomes from places
ranging from forested mountain tops
to hot deserts each cage contained a
microbiome from one of these places
along with sterilized dead grass for the
microbes to use as a food source
we then put the cages back into the
different habitats
so that the microbiomes experienced
pretty dramatic changes in climate
we expected that the microbes from the
cooler places would die out
when we moved them to the warm places
like the hot desert
and they would lose their ability to
consume and recycle the nutrients in the
dead grass material
but when we looked at the results i was
really shocked
the microbiomes were almost unfazed by
this massive climate difference
there were some changes in the dominant
species but mountaintop microbes
decomposed dead grass just as well as
desert microbiomes
in the hot dry climate this result tells
us that microbiomes have the ability to
evolve
and shift to deal with really dramatic
climate changes
another way that soil microbiomes can be
part of the climate change solution
is by building healthy soil many soil
bacteria and fungi
ooze out sticky chemicals to glue
themselves onto soil surfaces
the glue and the microbes form these
biofilms that hold soil particles
together
this helps the soil resist erosion and
hold more water that’s available for
plants
microbes in their biofilms also play a
big role in soil carbon sequestration
many forms of carbon from plants like
sugars don’t last long in the soil
because they’re food for many organisms
including the microbes
but micro bodies and biofilms are made
up of complex chemicals
for example many microbes build cell
walls for protection
so the wall material has to be resistant
to biochemical attack
when the microbes die their corpses
especially those cell walls
can stick around for a really long time
maybe even
thousands of years in this way
soil acts a lot like a bank vault for
carbon
more carbon in the bank means healthier
soil and
less greenhouse gas buildup in the
atmosphere
microbes are sort of like the federal
reserve they can take cash
off the street in the form of these
plant sugars and lock it away in a
chemical vault
for long-term storage with the signs of
climate change becoming more and more
obvious
every day we need to figure out how to
adapt for sure some scary outcomes like
emerging microbial diseases
are definitely something we need to plan
for but microbes can be a part of the
climate solution
if we figure out how to leverage all
that microbiome diversity
to be honest though making sense out of
complex microbiomes is still a
big scientific challenge their
complexity is both a blessing
and a curse we’re only beginning to
understand all the strange and wonderful
microbial lifestyles
that have been evolving since the
origins of life on earth
this digital artwork called microbes
reimagined
does a great job of capturing that sense
of mystery
but one thing we do know for sure is
that microbes are
not just pathogens our lives literally
depend on them
so next time you take a breath outside
imagine
all those oxygen spewing cyanobacteria
floating around in the ocean
and when the time comes and you draw in
that last and final breath
take comfort in knowing that soil
microbes will be there
to turn your body into useful nutrients
even as we enjoy these benefits of
microbiomes climate
change remains a potentially existential
threat to our well-being
but dangerous climate change is not
inevitable at least not yet
with the right cutting edge research
diverse microbiomes could become a big
part of the solution to our climate
problem
thank you