Genomic vulnerability of a dominant seaweed species points to future-proofing pathways for Australia’s underwater forests

By Rebecca VanArnam, SRC Intern

Endemic to Australia, Phyllospora comosa “is a forest-forming seaweed inhabiting the south-eastern Australian coastline that supports vital ecosystem functions” (Wood, 2021) (Figure 1). Like other species, climate change is causing biological changes within seaweed and seaweed-dependent organisms (Wernberf, 2011). As climate change impacts this seaweed species in Australia, scientists look to find adaptation patterns that the organism may possess. An organism’s genome can be assessed and used to understand how organisms adapt to changing environments.  

Figure 1: A photograph providing an image of Phyllospora comosa at a restoration site. (a) Represents an area that was restored (b) represents donor Phyllospora comosa to the area. [Image source: Coleman, 2017]

The increasing destruction caused by climate change influences scientist’s to perform research and look to find possible solutions while using marine genomics to do so. “Seascape genomics” became a popular tool to assess the seaweed species, Phyllospora comosa, within this study that took place in Australia. Seascape genomics evaluates a species’ spatial movement and dependence on environmental factors, such as climate change, and what role that dependence plays in the structure of an organism’s genomic patterns (Liggins, 2019).  In this study, genetic turnover was measured against sea surface temperature allowing for the further understanding of which genes within Phyllospora comosa are more vulnerable to changing temperatures (Wood, 2021). 

The analysis found that the Phyllospora comosa have relatively high gene flow, which means that their genetic material passes from one population to another, connecting their generations. The results also showed that genetic diversity was lower close to the edges of the species’ range. When linking these results to future climate change and fluctuating temperatures, it became evident that ocean warming is a definite threat to the populations where local adaptation is most likely occurring (Figure 2). This causes the central range, where diversity is highest, to be recognized as the most vulnerable area for the Phyllospora comosa (Wood, 2021).

Figure 2: A close-up photograph of the complexity of Phyllospora comosa [Image source: Wikipedia/ Phyllospora comosa]

Overall, the genetic methods used to analyze this data need to be used further to model patterns that can be developed and used to describe “genetically desirable populations” to protect this critical endemic seaweed. Not only are these methods needed for Phyllospora comosa, rather they have become and should continue to become understood and used as essential resources to help reduce climate change effects (Wood, 2021). 


Works Cited: 

Coleman, M. A., & Wernberg, T. (2017). Forgotten underwater forests: the key role of fucoids on Australian temperate reefs. Ecology and Evolution, 7(20), 8406-8418.

Liggins L., Treml E.A., Riginos C. (2019) Seascape Genomics: Contextualizing Adaptive and Neutral Genomic Variation in the Ocean Environment. In: Oleksiak M., Rajora O. (eds) Population Genomics: Marine Organisms. Population Genomics. Springer, Cham.

Wernberg, Thomas, et al. “Seaweed Communities in Retreat from Ocean Warming.” Current Biology 21.21 (2011): 1828-32. Print.

Wood, Georgina, et al. “Genomic Vulnerability of a Dominant Seaweed Points to Future‐Proofing Pathways for Australia’s Underwater Forests.” Global Change Biology (2021). Print.