1 23 Coral Reefs Journal of the International Society for Reef Studies ISSN 0722-4028 Volume 30 Number 3 Coral Reefs (2011) 30:643-650 DOI 10.1007/ s00338-011-0750-6 Genotypic diversity and distribution of Ostreobium quekettii within scleractinian corals Eldad Gutner-Hoch & Maoz Fine