Ms Soren Huber Schipper1, Blake Ramsby1, Florita Flores1, So Young Jeong2, Muhammad Abdul Wahab1, Andrea Severati1, Andrew Negri1, Guillermo Diaz-Pulido2
1Australian Institute of Marine Science, Townsville, Australia, 2 Griffith School of Environment, Coastal and Marine Research Centre, and Australian Rivers Institute – Coast and Estuaries, Brisbane, Australia
Crustose coralline algae (CCA) are fundamental to the health of marine ecosystems in the tropics. They are the mortar binding reef together and species-specific mediators of coral larval settlement and metamorphosis as well as other invertebrate taxa. It is well known that light is an important driver in marine ecosystem processes, yet less is known about how light intensity and quality impact CCA communities, including in aquaculture settings. In this study, we tested the influence of light spectra and irradiance on CCA community structure and composition growing on artificial substrates in culture. Settlement tiles were conditioned with CCA in flow-through tanks at the Australian Institute of Marine Science (Townsville), and then separated into aquaria exposed to three different light spectra (blue dominated, green dominated, and full-spectrum) at four distinct irradiance levels (ranging from 5 to 220 umol). DNA sequencing and morpho- anatomy were used to identify algae. Initial results indicated that light quantity impacted community composition and the morphology of the algae, but spectrum had no considerable influence on species composition. Communities were dominated by Lithophyllum sp. followed by Porolithon spp. and Mesophyllum spp. Results from this study may help inform optimal light conditions for propagating target CCAs for the purpose of settling coral in aquaculture and reseeding coral populations in degraded regions of the Great Barrier Reef.
