Tarrant, A.M., Atkinson, M.J., and Atkinson, S.  Effects of steroidal estrogens on coral growth and reproduction.  Marine Ecology Progress Series 269: 121-129, 2004.
© Inter-Research

Notes: Steroidal estrogens are well-described vertebrate hormones that also occur in invertebrates, where they have diverse biological effects. Estradiol-17beta is contained in coral tissues and released into the surrounding water during multi-species coral mass-spawning events. Estrogens are also widely distributed environmental pollutants in coastal waters; thus corals and other reef invertebrates are exposed to a variety of estrogens and estrogen-like compounds with unknown organismal and ecological effects. Until now, there has been no experimental evidence to suggest that estrogens are biologically active in corals. We describe the effects of exogenous estradiol on the size and number of gametes spawned by coral colonies and the effects of estrone on coral growth rates and tissue thickness. Montipora capitata coral colonies treated with estradiol for 3 wk prior to spawning released fewer egg-sperm bundles than controls (29% decrease). Porites compressa coral fragments ('nubbins') exposed continuously to estrone for 2 to 8 wk had lower (13 to 24%) skeletal growth rates than controls. Large coral nubbins that were treated with estrone had thicker tissue. While the mechanism for estrogen action for corals remains unknown, these experiments represent the first account of biological activity of steroidal estrogens in coral.