The role of algal reproduction in phylloid algal buildups: a case study in Pennsylvanian phylloid algae in southern Guizhou, China

The well-preserved reproductive morphology of Eugonophyllum within Pennsylvanian algal deposits in Guizhou Province, South China, provides a unique opportunity to study phylloid algal ecology and its role in carbonate buildups. Vegetative reproduction, characterized by the branching growth of algal segments followed by lateral budding in young thalli, appears to be the primary mechanism for maintaining and continuously increasing the population in the community. This method provides a dense, stable framework and bioclastic sediments for the development of lateral growth. Sexual reproduction occurs among mature thalli (comprising approximately 5%–10% of the population) and is characterized by synchronous gamete release. The synchronous spawning periodically increases the population and controls reef growth by the superposition of alternating generations. The combined effects of intrinsic factors of phylloid algae (rapid growth and reproductive strategy) and extrinsic factors (nutrient availability, ocean chemistry, seawater temperature) contributed to the dominance of phylloid algae in reef ecosystems in tropical-subtropical regions during the Pennsylvanian. Detailed evidence of Eugonophyllum growth and reproduction reveals the widespread distribution and high productivity of phylloid algae, opening new insights into global algal reef ecosystem blooms.