Nanodelivery of lipids to coral larvae maximises post-settlement survival: Implications for larval ecology and reef restoration.

Abstract

Interest in reef restoration is increasing as coral mortality has accelerated at an unprecedented rate. However, high mortality rates of coral early-life stages represent a population bottleneck, which directly impacts the effectiveness of restoration projects. While most coral larvae are considered lecithotrophic and catabolise maternally transmitted lipids to meet metabolic demands; here we demonstrate that coral larvae can be facultative feeders. We used nanoparticles to deliver triacylglycerides to aposymbiotic larvae which resulted in a 30% increase in larval energetic lipids, and a 46% increase in survival rate, up to 16 weeks post-settlement. Changes in phospholipid molecular species in the larvae suggest phagocytosis of the nanoparticles, and an increase in free fatty acids indicates lipolysis of the phagocytosed triacylglycerides. We suggest that a continuum of nutritional strategies should be recognised in coral early-life stages, and that nanoparticles can be used by restoration practitioners to deliver nutritional resources to maximise restoration outcomes.