The environment sustains humanity and all life on Earth. As we celebrate World Environment Day and World Ocean Day this week, we want to highlight the diverse microbes that protect these ecosystems. Since ecosystem functions are intimately linked to their residing microbial communities, this #FEMSmicroBlog by Sarah Wettstadt aims to show how microbes support the health of the ocean and environment and thus of each one of us. #MicrobiologyEvents
Microbes supporting plant health and growth
All plants on Earth harbour microbial communities. Especially within the rhizosphere, plants and microbes have intimate relationships, which are crucial for plant function and crop production. However, environmental conditions like droughts impact soil bacterial communities thus threatening this delicate balance and consequently, the surrounding ecosystem.
The research article “The effect of successive summer drought periods on bacterial diversity along a plant species richness gradient“ by de Souza et al. in FEMS Microbiology Ecology (2025) explores how repeated droughts affect bacterial diversity and consequently, the surrounding phytodiversity. The study explores how the relationships between soil microbes and their associated plants change over a period of nine years.
- Read the #FEMSmicroBlog: Repeated long-term droughts change the interactions between plants and microbes
Soil salinization, influenced by climate change and human activities, is another major form of soil degradation that needs to be addressed. However, microbes provide hope for improvement. Halo-tolerant, plant growth-promoting rhizobacteria appear to be a valuable biological tool in helping plants mitigate the effects of high salt concentrations and improving plant growth.
Highlighting advances in multiomics technologies, “Halo-tolerant plant growth-promoting bacteria-mediated plant salt resistance and microbiome-based solutions for sustainable agriculture in saline soils“ by Li et al. in FEMS Microbiology Ecology (2025) reviews molecular mechanisms of halo-tolerant rhizobacteria. The authors address the issue of plant losses in saline soil and how microbes offer solutions to combat the problem to ultimately improve global agricultural sustainability and food security.
Adding a fungal perspective, the article “Environmental and host plant effects on taxonomic and phylogenetic diversity of root fungal endophytes“ by Farrer et al. in FEMS Microbiology Letters (2025) investigated how plant-associated fungal communities are shaped by salt concentrations. Interestingly, it seems that host plants cultivate specific fungal taxa to help adjust to the environmental stress, thus using fungal endophytes to shape their own fate.
Microbes living in unexpected environments
Microbes have the astonishing ability to use a broad spectrum of energy and carbon sources. That’s why they can colonize even the most extreme habitats on Earth, from sulfidic lagoons to the deep ocean biosphere. Their adaptability continues to challenge our understanding of biology, opening avenues for countless discoveries.
For example, in dark and anoxic environments, some microbes can produce and consume oxygen without light. The minireview “Widespread occurrence of dissolved oxygen anomalies, aerobic microbes, and oxygen-producing metabolic pathways in apparently anoxic environments“ by Ruff et al. in FEMS Microbiology Ecology (2025) discusses how these microbes produce oxygen in dark environments. These findings defy our previous notions of what is possible and can have serious implications for subsurface biogeochemistry and ecology.
Another study looks into oil reservoirs. Even though oil reservoirs are primary sources of hydrocarbons, the pristine microbial communities in these untapped reservoirs are little explored. The study “Metagenomic analysis of pristine oil sheds new light on the global distribution of microbial genetic repertoire in hydrocarbon-associated ecosystems“ by Plewka et al. in microLife (2025) discovered microbes which are able to degrade methane, n-alkanes, mono-aromatic, and polycyclic aromatic compounds in a subsurface reservoir in the Barents Sea. These are exciting insights into microbial metabolism in an undiscovered environment.
Even in the frozen seas around Antarctica, there are diverse and abundant communities of microorganisms, with many endemic species occurring nowhere else in the world. The study “Psychrotrophic Antarctic marine bacteria as potential reservoirs for novel antimicrobial genes“ by Hwengwere et al. in FEMS Microbes (2025) identified novel biomolecules from Antarctic marine bacteria with antagonistic activities against known pathogens.
We are only beginning to recognize the resilience of microbes in these extreme conditions. Nonetheless, these newly found microorganisms may possibly be sources of solutions to many social challenges.
Microbes in the ocean
Marine microbes play crucial roles in regulating global nutrient cycles. To adapt to nutrients during seasonal changes, they adjust their metabolisms to balance cell growth and maintenance. The study “Prokaryotic Morphological Features and Maintenance Activities Governed by Seasonal Productivity Conditions“ by Verma et al. in FEMS Microbiology Ecology (2025) explores how changing growth rates can influence resource allocation at the levels of morphological features and metabolic adaptations.
In polar marine ecosystems, phytoplankton are primary producers. However, because their production rates vary from year to year, ecosystem functioning also changes accordingly. Higher growth rates of phytoplankton and total mortality during warmer seasons suggest that global warming increases the ocean carbon flow.
The study “Temperature-induced changes in the relevance of viral lysis and microzooplankton grazing of Antarctic phytoplankton indicates future alterations in seasonal carbon flow“ by Biggs et al. in FEMS Microbiology Ecology (2025) looked at how viral lysis impacted grazing rates and phytoplankton communities varied with seasonal changes. As such, this study sheds light on the ocean’s efficacy as a carbon sink.
Algal blooms are recurring events that sequester large amounts of carbon dioxide. Microalgae produce nearly half of the oxygen on our planet, making them key players in the global carbon cycle.
Understanding algal-bacterial interactions and carbon export during blooms in shallow waters might help combat the climate crisis. The study “Marine particle microbiomes during a spring diatom bloom contain active sulfate-reducing bacteria“ by Siebers et al. in FEMS Microbiology Ecology (2025) analyzed how microbial communities contribute to the global carbon cycle during a spring bloom in the North Sea.
From supporting crops in degraded soils to thriving in oil reservoirs and polar seas, microbes depict nature’s incredible adaptability. Their role in maintaining and supporting ecosystem functions cannot be overstated. As we reflect on our impact this World Environment Day and World Ocean Day, let’s also celebrate our microscopic allies silently working to keep the planet healthy.
About the author
Dr Sarah Wettstadt is a microbiologist-turned science writer and communicator writing for professional associations, life science organisations and researchers from the biological sciences. She runs the blog BacterialWorld to share the diverse and colourful activities of microbes and bacteria, based on which she co-published the colouring book “Coloured Bacteria from A to Z“. As science communication manager for the Scientific Panel on Responsible Plant Nutrition and blog post commissioner for the FEMSmicroBlog, Sarah writes about microbiology and environmental topics for various audiences. To help scientists improve their science communication skills, she co-founded SciComm Society, through which she offers guides, webinars and 1-on-1 coaching. Prior to her science communication career, Sarah completed a PhD at Imperial College London, UK, and a postdoc at the CSIC in Granada, Spain. In her non-scicomm time, she enjoys playing beach volleyball on the sunny beaches in Spain or travelling the world.
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.
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