Meeting Abstract

62.8  Wednesday, Jan. 6  The Interstitial Encrusting Fauna of Subtidal Sand, a Significant Understudied Habitat. WINSTON, Judith E.*; MIGOTTO, Alvaro E.; VIEIRA, Leandro M.; Virginia Museum of Natural History; CEBIMar, University of Sao Paulo, Brazil; CEBIMar, University of Sao Paulo, Brazil judith.winston@vmnh.virginia.gov

Studies carried out at two subtidal sand bottom sites, off the Florida east coast in 1982-4 and off the coast of São Paulo State, Brazil in 2002, showed assemblages of encrusting bryozoans utilizing the surfaces of mineral grains and sand to gravel size shell fragments, both at the sand-water interface, and interstitially. Larvae of sand encrusting species settled preferentially on different sized sand and shell grains. Colonies also became sexually reproductive at much smaller sizes than colonies of species occupying larger substrata The mixed terrigenous and carbonate sand habitats also supported other kinds of encrusting organisms such as serpulid and spirorbid polychaete worms, hydroids, entoprocts, and forams, as well as the more familiar motile meiofauna. Twenty-two exclusively interstitial encrusting species have been found at the two areas so far. A re-collection at the one of the Brazilian stations in July 2009 found the same species thriving as in November 2002, indicating the persistence of the community despite its unstable environment. At both the Florida and Brazilian sites living and reproductive colonies of bryozoan species characteristic of larger subtidal hard substrata, were found on sand or gravel size grains, indicating the potential importance of an interstitial refuge in maintaining and dispersing subtidal and shelf encrusting organisms even where larger substrata are absent and taxa have short-lived larvae.