#FEMSmicroBlog: How does the climate change affect microbial communities


The International Microorganism Day is upon us. And with it our call to recognise what microbes do for our daily lives, the environment and the global climate. Unfortunately, climate change also impacts how microbes influence the geochemical nutrient cycles, local weather phenomena and ecological functions. Dr Sarah Wettstadt explains on the #FEMSmicroBlog how microbes impact the local and global climate and why the current climate change may also harm our microbial friends. #MicrobiologyEvents


Microbes impact the global climate by forming clouds

Microorganisms can live and thrive in clouds and airborne water droplets. And some bacteria and fungi can even start precipitation inside clouds due to special surface proteins. Interestingly, this process impacts the global bioprecipitation cycle.

Bioprecipitation is triggered by plants emitting water vapour into the air. These are filled with microorganisms – one way of plants to get rid of plant pathogens. However, some of these air-borne ice-nucleating microorganisms like Hemileia vastratrix and Pseudomonas syringae can cause cloud formation. Hence, rain falls providing plants and microorganisms with water so that they grow and thrive. Also, some microbes – especially bacterial pathogens – use this as transport mechanism to get spread around the globe.

Due to the limitations of cultivation methods, we currently can’t appreciate all microorganisms that live in the air around us. Yet, some studies estimate that around 100 cells – including bacteria, viruses, archaea and eukaryotes – live within a litre of air.


Microbiomes on sand dust can change distant ecosystems

Some air-borne microorganisms can also attach to sand particles. Like this, sand dust and sandstorms transport these organisms to new areas and ecosystems.

Interestingly, microorganisms hitchhiking on sand particles are highly stress-resistant and thrive under harsh environmental conditions. This includes water and nutrient restrictions, extreme temperatures and UV radiation. Just the right environment for spore-forming Bacillus or bacteria from the genera Modestobacter.

However, sand-associated microbiota can also impact human health or the local ecosystem to which they are transported. For example, dust from the Sahara Desert could influence meningitis outbreaks in the sub-Sahara African region. Also, microorganisms from the Sahara Desert can burden the coral reefs in the Caribbean

World map of dry lands and how the climate change impact the global areas of desert.
World map of drylands. From Behzad et al. (2018).


Microbiomes in deep seas impact global water ecosystems

Microorganisms living in deep-sea environments likely represent the most abundant biological components. They play important roles in global geochemical nutrient cycles. Even though life in this environment is food-limited, microorganisms can produce a plethora of organic molecules that impact other water layers.

The most abundant microorganisms in deep-sea sediments belong to Alveolata, Euglenozoa, Heterokonta and Rhizaria groups. While our knowledge of the complexity of microbial communities in the deep-sea levels is still scarce, it is known that with increasing water depth, the archaeal abundance increases. This likely goes along with more complex metabolic activities at these depths.

Chart of the cumulative (global) microbial biomass at the deep seafloor.
Cumulative (global) microbial biomass at the deep seafloor. From Danovaro et al. (2017).

Also, viruses are highly abundant in deep-sea water environments. These can infect bacteria or unicellular eukaryotes, especially in oxygen-depleted ecosystems. Hence, interactions amongst microbes – including virus-host interactions and eukaryote-predator grazing – shape local microbial communities. And these further impact water structures at different sediment levels.


Global climate change influences local microbial communities

Climate change impacts our planet in different ways: shifts in water temperature, pH or oxygen content; increasing desertification; land erosion and thus shifts in winds; as well as longer drought periods in tropical forests.

Schematic of how microbes impact the global climate and the climate change impact microbes.
Image from Microbiologists’ Warning to Humanity about how microbes impact the climate and climate change affect microbes.

Each of these regional changes impacts local microbial communities and thus their metabolic activities and capacities. These changes can then influence the regional but also the global climate.

For example, a change in the local microbial community in the deep-sea environment might not be able to buffer the impacts of global climate change. Or increasing desertification resulting in more sand particles transported around the globe will introduce more foreign species into new environments.

Hence, we need to think locally to act globally. Taking care of the microbial communities in your local environment helps to protect the planet from the global impact of climate change. Think of it as a microbe-induced butterfly effect and start acting now!

Happy International Microorganism Day!


About the author of this blog

Dr Sarah Wettstadt is a microbiologist-turned science writer and communicator working on various outreach projects and helping researchers talk and write about their scientific results. Her overall vision is to empower through learning: she shares scientific knowledge with both scientists and non-scientists and coaches scientists in writing about their research. Sarah is blog commissioner for the FEMSmicroBlog and was a social media editor for FEMS for 1.5 years. Previous to her science communication career, she worked as a postdoc in Marían Llamas’ lab on Pseudomonas aeruginosa’s ability to use heterologous iron sources and completed her PhD with Alain Filloux investigating the type 6 secretion system in Pseudomonas aeruginosa.

About this blog section

The section #MicrobiologyEvents for the #FEMSmicroBlog reports about events and meetings relevant to our network. These include world awareness days, FEMS-sponsored meetings or meetings of Member Societies and many more.

Do you want to be a guest contributor?
The #FEMSmicroBlog welcomes external bloggers, writers and SciComm enthusiasts. Get in touch if you want to share your idea for a blog entry with us!

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