Microbial diversity is estimated from samples
AI-generated conceptual illustration of sampling microbial life across different habitats; no counts or research results shown. Generated 2026-10-29. Prompt: “Vertical 4:5 editorial science illustration showing scientists sampling microbial diversity across Earth habitats: soil, ocean, freshwater, hot spring, and animal-associated environments connected to a laboratory sequencing setup, with stylized bacteria emerging from samples. Accurate but conceptual, no people faces, no text, numbers, percentages, charts, or logos.”
Counting bacterial diversity depends on which environments have been sampled and how a “species” is defined. In 2026, researchers analyzed 92,187 metagenomes from diverse habitats and predicted about 705,000 bacterial and 27,000 archaeal species-level clades discoverable in that dataset. This is not a complete census of every microorganism on Earth and does not show that 99% of bacteria remain unstudied.