PARENT SESSION
Poster Session # 20: Predator - Prey / Mutualism - Parasitism Ecology.

Thursday, August 7 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.

Determining the specificity of associations between marine sponges and symbiotic cyanobacteria.

Erwin, Patrick^*,1, Thacker, Robert¹, ¹ University of Alabama at Birmingham, Birmingham, AL

ABSTRACT- Symbioses observed between marine sponges and cyanobacteria have sparked both ecological and biotechnological interest. Associated cyanobacteria may benefit their host by providing additional nutrients (e.g. fixed nitrogen) and synthesizing anti-predatory and anti-fouling compounds. Sponges may benefit their cyanobacterial symbionts by providing nutrients through excreted waste products and a refuge from predation within the sponge mesohyl matrix. We examined the specificity of association between host sponges and their cyanobacterial populations for 15 Verongid sponges, including 7 species, 4 genera, and 2 families. Cyanobacterial 16S ribosomal DNA (rDNA) was amplified from whole-sponge genomic extracts. For each sponge specimen, 10 clones of cyanobacterial rDNA were isolated, PCR-screened using cyanobacteria-specific primers, and digested using 2 restriction enzymes. The resulting banding patterns were used as indicators of the diversity of cyanobacteria associated with each sponge specimen. Sponges in the genera Aplysina and Verongula hosted multiple genotypes of cyanobacteria. Of the 10 different observed banding patterns, 1 was exclusive to the genus Ianthella, 3 were exclusive to the genus Aplysina, and 4 were exclusive to the genus Verongula, suggesting genus-specific associations between eight cyanobacterial strains and their host sponges. The remaining 2 banding patterns were common to sponge specimens from different genera, suggesting a transient or generalist relationship between these two cyanobacterial strains and their host sponges.

Key words: cyanobacteria, symbiosis, porifera, mutualism