Dr Albert Pessarrodona Silvestre1, Dr Karen Filbee-Dexter1,2, Prof Thomas Wernberg1,2
1University Of Western Australia, Crawley, Australia, 2 Institute of Marine Research, His, Norway
Algal turfs are emerging as a common and widespread configuration of shallow temperate reefs worldwide. Yet, we still have a vague understanding of how turfs will affect ecosystem functions, and which ecosystem properties will change or be maintained. This talk will explore how the rise of turfs in temperate regions affects four important ecosystem properties: habitat structure, primary and secondary production, and sediment dynamics. Transitions from kelp forests to turf dominance across six temperate ecoregions consistently resulted in the flattening of underwater habitat structure, with turf seascapes occupying a smaller architectural trait space than forests, evidencing habitat homogenization across ecoregions. Turfs also increased reef sediment retention by up to 200%. Using the first global maps predicting seaweed NPP, we found that turfs supported up to 10 times less primary production per area than marine forests, suggesting the rise of turfs may decrease the amount of carbon entering coastal food webs and being assimilated by seaweed vegetation globally. Interestingly however, turf-driven trophic pathways can underpin the majority of herbivorous fish secondary productivity in reefs where marine forests have declined, as found tropicalized reefs in eastern Australia. This suggests that some turfs are highly palatable, and a greater proportion of the carbon assimilated via NPP can be directed to higher trophic levels in turf-dominated reefs, transforming energy flow and secondary producer’s biomass. These findings evidence algal turfs as emerging drivers of ecological processes in temperate reefs, hinting they will function in novel ways as they further transition into the Anthropocene.
Presentation Slides – Albert Pessarrodona
Biography:
Albert is a postdoctoral fellow at the University of Western Australia and Conservation International. His research focuses on the role macroalgae play in the coastal carbon cycle, the impacts of tropicalization in temperate ecosystems, and the redistribution of marine forests
