The Microscopic Elephant in the Room

Life as humans know it is slowly but surely being altered by the crucial issue of climate change (Tiedje, et al., 2022). Greenhouse gases (GHGs) such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), largely contribute to this problem and are in surplus due to altered biogeochemical cycles. These gases are produced and consumed by the most plentiful organisms on Earth known as microbes (American Society for Microbiology, 2022). Despite their abundance, microorganisms are largely ignored in the discussion of climate change even though they simultaneously are impacted by and impact the climate. This is of particular concern as microbial actions affect the stability of other organisms’ response to climate change (Cavicchioli, et al., 2019).

The term “microbe” is used to describe an organism of microscopic size including bacteria, fungi, viruses, archea, and protists (Tiedje, et al., 2022). They are found in all environments on the planet, including those inhabited by macroscopic organisms and extreme environments where other organisms cannot survive. While it is hard to imagine as they cannot be seen, microbes play a vital role in supporting the biosphere (Cavicchioli, et al., 2019).

The impact global warming and increased soil temperature have on soil microbial communities is vital to investigate. This is because changes to soil microbiome will impact nutrient availability and carbon and nitrogen cycles, raising concerns regarding crop growth and food security (Zhou, et al., 2012). Additionally, temperature and other physical changes to the soil due to climate change still have relatively unknown impacts on the environment as a whole (Andrade-Linares, et al., 2021). However, research shows that climatic changes, such as increased atmospheric concentrations of CO2, nitrogen deposition, and natural disasters, do significantly change the features of microbial communities. These changes to the soil have the potential to change the respiration and denitrification of microbes, ultimately leading to effects on their metabolism, nutrient feedback, and genetic diversity (Tian, et al., 2020). If these changes are not accounted for in future studies, the assessment of major GHGs will be inaccurate, interfering with models and climate mitigation strategies (American Society for Microbiology, 2022). 

Figure 1: A diagram depicting the positive feedback loop that occurs as climate change thaws permafrost. This allows frozen carbon pools to be exposed, allowing microbes to start processes that produce CO2 and CH4 (WWF Arctic Programme, 2022).

Changes to the microbial environment have the potential to dramatically change reservoirs that release or take in carbon, known as carbon pools (American Society for Microbiology, 2022). For instance, permafrost, or areas of continuously frozen soil, hold considerable amounts of carbon from residual plants, animals, and microbes (Schuur, et al., 2008). The permafrost has begun to thaw in certain areas as global temperatures shift, freeing up a large carbon pool. The resulting release of stored carbon allows microbes to use the organic matter for enzymatic processes, producing of CH4 and CO2. With this production comes a positive-feedback loop in which climate change thaws permafrost, allowing more CH4 and CO2 to be produced, which exacerbates already increasing temperatures. This feedback loop can be seen in Figure 1. These actions ultimately increase carbon levels in the atmosphere (American Society for Microbiology, 2022). 

While microorganisms can increase the rate of climate change, they could also be utilized to improve our climate models and enhance effective mitigation. In addition, enhanced microbial biotechnology can be used to improve the sustainability of agriculture, energy production and pollution. Nevertheless, more research is needed to develop these methods (Cavicchioli, et al., 2019).

Microorganisms can affect the climate, and in turn, the climate can affect them, thus they are a vital aspect of examining global warming and climate mitigation. However, there is much to be learned about their complex relationship in order to better interpret and predict trends to combat global warming. 


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