Note
This study demonstrates a symbiotic relationship between marine algae and the invertebrate embryos in gelatinous egg masses found in Indian River Lagoon, FL, USA. The benefits to the embryos in this association differ among host species investigated. The embryos of the polychaete Axiothella mucosa graze on the diatom assemblage in their egg masses and the fitness of the crawl-away juveniles is improved by this food source. The tenuous egg masses of the polychaete Arenicola cristata and the mollusk Haminoea succinea are negatively buoyant when spawned and become buoyant when symbiotic algae are present.