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Recent studies on extremophiles have focused on thermophiles, microbes that thrive in high temperatures, while psychrophiles, which prefer cold environments, have received less attention. However, interest in cold-adapted microbes, especially those in polar regions, has increased significantly in recent decades. Given that much of Earth’s biosphere remains below 5°C, psychrophiles likely outnumber thermophiles. Oceans, covering over 75% of the planet, maintain deep water temperatures between 2–4°C. Antarctica offers both terrestrial and aquatic cold habitats, including ice that melts seasonally. Other cold ecosystems include permafrost, alpine soils, cold deserts, marine sediments, glaciers, and sea ice