How did the floating Ulva prolifera develop into the world's largest green tide?

Area of Science:

• Marine biology
• Ecology
• Phycology

Background:

• The Yellow Sea experiences massive Ulva prolifera blooms, with the largest recorded 16 years ago.
• Despite source control measures since 2019, the rapid development of these green tides remains poorly understood.

Purpose of the Study:

• To investigate the growth mechanism of floating Ulva prolifera populations.
• To elucidate the factors contributing to the rapid development of green tides.

Main Methods:

• Examined the production and regeneration of Ulva prolifera explants.
• Constructed a population growth model for Ulva prolifera.

Main Results:

• Ulva prolifera explants showed rapid regeneration via branching at 15-25°C.
• Algivore feeding and sporulation at 20-25°C facilitated mass explant production.
• Coupling of mass production and rapid regeneration in multiple cycles drove the green tide outbreak.

Conclusions:

• A novel population growth model explains the Ulva prolifera green tide outbreaks.
• Understanding explant dynamics is crucial for managing macroalgal blooms.