In the pink – new coralline algae programme
Science Centres: Aquatic Biodiversity and Biosecurity
Intertidal coralline algae near the mouth of Ohau Stream, north of Kaikoura (photo: K. Neill).
The least studied of New Zealand’s macroalgal flora may be one of the most important – at least as far as paua and other marine fauna are concerned. Ministry of Fisheries funding recently awarded to NIWA is seeking to address the lack of knowledge of this abundant and diverse group of organisms – the crustose coralline algae.
Crustose or nongeniculate coralline algae (NCA) are red algae that deposit calcium carbonate in their cell walls, and they play a crucial role in coastal ecosystems. Many corallines have a major role in producing chemicals that promote the settlement of invertebrate larvae. Paua habitats are rich in coralline algae, and research in southern Australia shows that, for at least one species of paua, the larvae settle preferentially on a particular species of coralline. Species of limpets, crabs, and rock lobsters also have critical relationships with corallines. For example, rhodoliths (unattached, free-living corallines) are important refuge and nursery sites for fish and invertebrate species.
Coralline algae grow throughout the world’s oceans from intertidal to subtidal regions. The deepest corallines found in New Zealand come from the clear, warm waters around the Kermadec Islands, where they have been dredged from depths of 200 m. Nongeniculate coralline algae are important in the construction and ecology of coral reefs, acting as the main cementing agent and providing calcareous material for the structure of the reef. Research suggests that the calcium carbonate in the cell walls of NCA may be one of the largest stores of carbon in the world.
We do not know much about these ecologically important organisms in New Zealand, and there has long been a need to document our NCA species to understand their ecological characteristics, the differences between species, and any regional differences. Basic information – how many species we have, where they grow, and their interactions with other algae and key invertebrate species – is sparse or completely lacking.
This year the Ministry of Fisheries recognised the importance of NCA to marine ecosystems in New Zealand by awarding NIWA biodiversity research funding to document the NCA of central New Zealand over the next two and a half years. The programme, led by NIWA scientist Wendy Nelson, will draw on the expertise of Bill Woelkerling and Adele Harvey (both based at La Trobe University in Melbourne), who between them have 35 years experience researching the NCA of Australia. Judy Broom at the University of Otago will use molecular biology tools to identify New Zealand’s NCA species, and to help us understand the relationships of the New Zealand flora.
The programme will collect samples of NCA primarily from central New Zealand, with the aim of establishing baseline collections that will form the basis for research on the flora. In early September, collectors from NIWA, Department of Conservation, and University of Canterbury attended a workshop for initial training on collecting and processing NCA. Further workshops on the identification of New Zealand coralline algae will be offered at a later date and an identification guide produced. For more information, contact Wendy Nelson.