Aerobatic Algae: Skyward Tango of Microbial Marvels

Diatoms are microscopic algae encased in intricate glass shells, floating almost invisibly within bodies of water ranging from oceans to puddles. Despite their tiny size, their impact on the environment is immense. Diatoms generate about 20% of the oxygen we breathe, meaning every fifth breath you take owes its existence to these minuscule organisms.

Biological Significance

Diatoms have fascinated biologists for centuries due to their delicate beauty and variety. These single-celled organisms are crucial to the aquatic food web and play a significant role in global carbon cycling. When they die, their siliceous (silicon dioxide) shells contribute to sediment formation, impacting geological processes over millennia.

Discovery of Diatom ‘Dance’

Recently, scientists discovered something remarkable about diatoms: they ‘dance’ when illuminated with light. This peculiar oscillatory movement involves zigzagging around in spiraling paths or swimming straight before making sudden turns by rolling, akin to miniature acrobats performing a choreography. The dance has been described as a ‘tango,’ complete with rhythm and patterns.

Mechanism Behind the Dance

For years, the mechanism driving this dance remained unknown until researchers from Université Paris-Sud made a groundbreaking discovery. They found that the dance involves light, buoyancy, and gravity. When light hits their siliceous shells, some wavelengths are absorbed and converted into heat, causing temperature increases at certain spots on the organism’s body—a phenomenon known as the photothermal effect.

The temperature difference generates currents around the warmer region due to differences in fluid density caused by heating (thermal convection). This thermal convection, combined with the alternating heavy-light status caused by photosynthate accumulation and consumption, creates variations in buoyancy, leading to their characteristic motions.

Ecological Importance

These unique motility mechanisms allow diatoms to mine nutrients efficiently while suspending themselves within the euphotic zone, where sunlight penetration is conducive to photosynthesis. This enables them to thrive under nutrient-limiting conditions while outshining other competing phytoplankton species.

Conclusion

The discovery of diatom dancing accentuates the importance and complexity of these tiny organisms, which play a significant role in maintaining planetary health. It underscores that small does not necessarily mean insignificant; these microscopic dancers hold big ropes in sustaining life on Earth through oxygen production and nutrient cycling.