Microorganisms, tiny but mighty, play a critical role in maintaining the health and function of Earth’s biodiversity and ecosystems. They are incredibly diverse and can be found everywhere, from volcanoes to freezing polar regions. Microbial diversity encompasses not only taxonomic diversity but also functional diversity, as each microorganism’s interaction is unique, with various metabolic capacities, activities, and interactions in each specific ecosystem [1][2].

What Are Primary Producers?

Almost all life on Earth depends directly or indirectly on primary production. Primary producers, also known as autotrophs (“self-nourishers”), are organisms that harness energy from sunlight and gather materials from non-living sources[3].

Photosynthesis is the key to primary production. Algae, cyanobacteria, and plants possess the unique ability to capture energy from the sun and combine it with inorganic or non-living materials, like carbon dioxide and water. This process results in organic molecules, such as oxygen and glucose, which serve as the fuel for all other living things. Hence, primary producers form the foundation of all food chains, and therefore of biodiversity. Without them, life on Earth as we know would not exist[3].

Primary Producers and the Food Chain

Figure 1. Primary Producers and the Food Chain[5]

Microbes as Primary Producers


Phytoplankton, including Cyanobacteria and microalgae, are vital primary producers that are not limited to specific environments – they can be found in both land and water. Their photosynthetic activities are responsible for 50% of global primary production[4].

Cyanobacteria, also known as blue-green algae, are crucial in converting carbon dioxide and water into energy through photosynthesis, producing oxygen. This process contributes significantly to oxygen levels in Earth’s atmosphere[6].

Examples of cyanobacteria and microalgae from the Baltic Sea

Figure 2. Examples of cyanobacteria and microalgae from the Baltic Sea: Pseudanabaena catenata (A), Nostoc edaphicum (B), and Nostoc sp. (C)[7].

These Cyanobacteria have been around for an incredible 3.5 billion years! Scientists believe these microbes have played a crucial role in oxygenating Earth’s atmosphere during the Precambrian supereon. Which in turn, helped make it possible for oxygen-dependent life on Earth[6].


In ecosystems with insufficient sunlight for photosynthesis to occur, organisms called chemoautotrophs provide energy. Mostly bacteria and other microorganisms break apart inorganic chemical compounds – such as hydrogen sulphide, iron, and magnesium. They then use the energy released to make organic molecules. Chemoautotrophs include bacteria located in the soil, iron oxidizing bacteria located in the lava beds, and sulphur oxidizing bacteria located in deep ocean thermal vents thereby sustaining life in these environments[8].

Microbes Offer Solutions

Many microbes are capable of generating potential energy-producing products, like biofuel, bioelectricity, and biohydrogen through their metabolic process. This occurs particularly among photosynthetic microorganisms[8]. Additionally, there is ongoing research into bioremediation – the use of microorganisms to break down environmental pollutants- which could potentially mitigating climate change[9].

On Biodiversity Day, it is important to acknowledge the significant role of microorganisms in preserving biodiversity and ecosystem stability. In the face of climate change, it becomes increasingly crucial to understand the influence of microbes. Through promoting research and public awareness, we can enhance our understanding of the diverse microbial communities and interactions that are fundamental to the wellbeing of the planet [9].


  1. https://www.ncbi.nlm.nih.gov/books/NBK580166/
  2. https://www.nature.com/articles/ncomms10541
  3. https://link.springer.com/chapter/10.1007/978-1-4020-5583-6_6
  4. https://www.nature.com/articles/s43705-022-00149-w#Sec16
  5. https://microbiologysociety.org/why-microbiology-matters/what-is-microbiology/microbes-and-the-outdoors/food-chain.html
  6. https://www.tandfonline.com/doi/full/10.1080/17429145.2023.2242697
  7. https://www.sciencedirect.com/science/article/pii/S016041201931400X
  8. https://eprajournals.com/IJIR/article/6524/download
  9. https://asm.org/ASM/media/Policy-and-Advocacy/Climate-Policy-Paper-2022.pdf

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