A coral colony appears firmly attached to the reef, but some stages of coral reproduction take place away from that fixed setting. Broadcast spawning is one way the story moves into the water column.
Many corals release eggs and sperm into the water; fertilisation can lead to larvae that later settle. NOAA’s coral reproduction tutorial also describes other reproductive pathways, so one dramatic spawning video should not stand for every coral species.
Follow the stages carefully
In your notes, distinguish release of reproductive cells, fertilisation, larval development and settlement. They are connected stages, not interchangeable names for the same visible event.
A video of material leaving a colony does not directly show how many new colonies will eventually establish. Many conditions and losses intervene between release and successful settlement.
When reading a report, keep the species, location and observation date attached to it. Timing described for one reef should not become a universal calendar for all reefs.
Try sketching the sequence with a question mark beside any stage the report did not observe. This makes the limits of the evidence visible without diminishing the event itself. The reef’s next generation begins through processes that a single spectacular image can only partly capture.