Figure 1. Possible cause-effect pathways in which suspended solids (SS) can reduce fertilisation rates in broadcast spawning corals.

Clockwise from top left, SS could impact egg viability through damage to the egg or through impacting the polyspermy block. Similarly, SS could impact sperm viability from toxic substances leached from the sediment, physically through abrasion, or by depleting energy reserves via increased flagellum beating. SS could also decrease egg-sperm contacts and sperm penetration by damage to anchoring protrusions on the egg (microvilli), by impairing the sperm chemoattractant, by cloaking of the gametes, slowing and blocking sperm, and by entanglement and sinking of the sperm.