Floating lecithotrophic eggsfrom the bathyal echinothuriid sea urchin Araeosoma fenestratum

The large lecithotrophic eggs of the bathyal echinothuriid sea urchin Araeosoma fenestratum are positively buoyant both in vitro and in situ. In the laboratory, some eggs of A. fenestratum were negatively or neutrally buoyant at 10⁰C, but all eggs were positively buoyant at higher te mperatures (> 15⁰C). In situ, all eggs were positively buoyant from the surface to 790 m depth, spaning temperatures of 9⁰ to 27⁰C. At constant salinity, flotation rate is directly related to temperature; eggs ascend more slowly at colder temperatures. We predict that eggs of A. fenestratum could reach the surface from a depth of 800m in 4.2 days. ; Florida Atlantic University. Harbor Branch Oceanographic Institute contribution 598 ; This manuscript is an author version with the final publication available and may be cited as: Cameron, J. L., McEuen, F. S., & Young, C. M. (1988). Floating lecithotrophic eggs from the bathyal echinothuriid sea urchin Araeosoma fenestratum. In R. D. Burke, P. V. Mladenov, P. Lambert, & R. L. Parsley (Eds.), Proceedings of the Sixth International Echinoderm Conference, Victoria, 23-28 August 1987 (pp. 177-180). Rotterdam; Brookfield, VT: A. A. Balkema.