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Evolutionary Impact of Glacier Algae
Context:
Scientists from the UK and Canada traced purple algae evolution over hundreds of millions of years, challenging key evolutionary concepts.
Thriving in Extreme Environments:
- Glacier algae, despite their minuscule size, have evolved remarkable adaptations to thrive in one of Earth’s most extreme habitats.
- They significantly impact glaciers by darkening ice surfaces, which accelerates melting during summer
Adaptations and Genetic Discoveries:
- Research published in New Phytologist involved sequencing the genome of Ancylonema nordenskioldii.
- The study revealed that purpurogallin, their purple pigment, functions as a sunscreen protecting them from UV and visible light, essential for their survival.
- Moreover, novel genes that enhance light tolerance were identified, underscoring their advanced mechanisms for perceiving and repairing light damage.
Evolution in Earth’s History:
Glacier algae trace their origins back to 520-455 million years ago, evolving during Earth’s colder periods, such as the Cryogenian.
- They share a common ancestor with land plants from this era, demonstrating adaptation to extreme cold environments.
Simplification as an Evolutionary Strategy:
- Contrary to traditional views of evolution, glacier algae have simplified over time, losing multicellularity and genetic complexity linked to development.
- This adaptation to a simpler form has proven advantageous in their survival on icy surfaces.
Ecological Impact:
- Specialised to glaciers, few algae species possess these adaptations compared to those on snow.
- Their growth significantly affects ice fields, notably increasing runoff in regions like the Greenland ice sheet.
- Understanding their evolution aids predictions regarding Earth’s icy environments amidst climate change.
