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BAMOS April 2025
15 sperm. Fertilised eggs grow into baby Giant Kelp on the female gametophytes. At its peak, Giant Kelp can grow 50 centimetres in a single day.
Divers take cuttings from the reproductive blades of Giant Kelp individuals to provide gametophytes to culture in the lab. Under red light at 4 degrees Celsius, gametophytes remain in stasis. We can store them as a biobank, which is like a seed bank of Giant Kelp to help secure the species.
At 12 to 15 degrees, they produce more cells, which we can use for study. Blue light triggers sperm from male gametophytes to fertilise egg cells from female gametophytes. Our partners grow Giant Kelp babies on lengths of string and plant them in the ocean.
Cuttings of Giant Kelp collected from a beach in Hobart. Credit: CSIRO
Giant Kelp babies attached to twine for planting in the ocean, growing in the labs at the Institute for Marine and Antarctic Studies( IMAS). Credit: CSIRO
Secrets in the DNA
Thanks to studies at the Institute for Marine and Antarctic Studies( IMAS), we know some Giant Kelp individuals are more tolerant of warmer sea temperatures.
We are using genomics to understand why. One of the techniques we are using is whole genome sequencing. This means looking at the entire DNA sequence of Giant Kelp individuals and testing whether genetic differences are associated with thermal tolerance.
To help analyse the huge and complex data, we are using two Google AI tools: DeepConsensus and DeepVariant. So far, we have found some initial evidence that thermal tolerance in Giant Kelp does indeed have a genetic basis. This means we’ ll be able to use selective breeding techniques to breed thermally tolerant Giant Kelp babies for replanting in the ocean.
As populations of Giant Kelp decline, they risk permanent loss of genetic diversity, further diminishing their chances of survival. That’ s why we’ re also looking at the genetic structure of the remnant populations of Giant Kelp in the coastal waters of eastern Tasmania.
We want the breeding program to maximise the trait of thermal tolerance while maintaining the full genetic diversity present in Tasmania’ s remnant Giant Kelp populations.
We have found remnant Giant Kelp populations have more genetic diversity than we expected, which is good news for the species. We’ ve found genetic differences between the populations in the north-east of Tasmania and the southern populations near Hobart. The southern populations have higher genetic diversity.
Forests of the future
Our ongoing work to understand Giant Kelp populations, and select warm tolerant strains for replanting, will give Tasmania’ s Giant Kelp forests the best chance to recover and flourish into the future.
Unravelling the genetics of Giant Kelp could also support farming Giant Kelp for biomass to lock away carbon. Find out how Giant Kelp and other seaweeds hold promise for a net zero future.
Acknowledgements
This project is a partnership between Google Australia( supported by the Digital Future Initiative), CSIRO, the University of Tasmania’ s Institute for Marine and Antarctic Studies( IMAS) and The Nature Conservancy( TNC).
CSIRO, IMAS, and Google researchers are using two Google AI tools- DeepConsensus and DeepVariant- to analyse surviving Giant Kelp to understand what makes some of it heat resistant and ensure genetic diversity and increased thermal tolerance in restored forests.
TNC identifies sites most suitable for Giant Kelp restoration. IMAS grows Giant Kelp strains for around six weeks before TNC and IMAS plant the Giant Kelp at the restoration sites using a technique developed by IMAS to attach the juvenile Giant Kelp to the sea floor.
This article was republished with permission from Andrea Wild, CSIRO.