Sediment burial reduces coral larval settlement, recruit survivorship, and inhibits the recovery of coral populations

The recovery of coral populations depends on successful settlement and survivorship of recruits. Sedimentation is a major stressor for corals, yet information on its influence on Caribbean juvenile corals is limited. We evaluated larval settlement and recruit survival under sediment burial across six Caribbean species and multiple early life stages. Burial of suitable substrata under 2 mm of sediment reduced settlement probability to ≤25% and 4 mm suppressed settlement entirely. Similarly, the burial of coral recruits under 4 mm of sediment decreased survival probability to 0-31% within ten days and increased mortality risk 3- to 25-fold relative to unburied corals. Field surveys across the Florida Reef Tract corroborate that sediment trapped within long, sediment-laden algal turf (LSAT) is a significant, negative predictor of the presence of coral recruits. Our results reflect the urgent need for managers to limit future declines in reef-habitat quality to promote coral recovery.