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