Dr Aimee Van Der Reis1, Professor Mary Sewell1, Professor Wendy Nelson1
1University Of Auckland, Auckland, New Zealand
Biography:
Aimee van der Reis is a postdoctoral fellow based at the University of Auckland. Aimee's interests lie in using modern molecular techniques to unpack complex questions typically associated with the marine environment. She is particularly interested in using DNA metabarcoding for marine conservation and management purposes. She is currently involved in a Marsden research project that is investigating whether crustose coralline algae act as a seed bank in marine ecosystems.
Abstract:
Dormant stages of phytoplankton and seaweeds have recently been found inside rhodoliths, nodular forms of crustose coralline algae (CCA). It is plausible that given CCA are long-lived, relatively resilient to environmental change, and have resident dormant algae, that they act as the marine equivalent of a terrestrial seed bank. Our 2023 preliminary DNA metabarcoding study emphasized the possibility of this. Two shallow-water species of (thick) encrusting CCA were collected from the Kermadec Islands, New Zealand. The presence of algae in the inner and outer regions of the crusts was investigated by targeting seven gene regions: 16S, 18S, 23S, COI, ITS, rbcL, and tufA. We found unexpectedly high biodiversity within the inner layers of the CCA at both micro- and macroscopic levels, confirming the findings of previous studies on rhodoliths whose results show a high diversity and abundance of marine species. The 23S and rbcL genes were more suitable for identifying algae, while the COI gene fared better at capturing the diversity present inclusive of algae. Our current research expands this work, examining the biodiversity in rhodolith and encrusting CCA specimens (n=125) from multiple collection sites in mainland New Zealand. Four gene regions have been selected from the seven previously tested (COI, 23S, 18S, and rbcL), as these regions were identified to be more promising for capturing New Zealand’s algae diversity. We hypothesize that there will be local differences in the algal taxon composition in the CCA samples.