Dr Guillermo Diaz-Pulido

Postdoctoral Fellow

Kathleen Broderick

 

Postdoctoral Research Fellow,
Pew Program in Marine Conservation.
University of Queensland

Research Interests
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Research Interests

My research focuses on the population and community ecology of coral reef macroalgae (seaweeds), particularly in the context or coral reef degradation and global climate change. My recent work in the Colombian Caribbean and the Great Barrier Reef has focussed on understanding the processes and interactions regulating macroalgal abundance on coral reefs. I am interested in the roles of ecological processes such as recruitment, eutrophication, overfishing, and coral disturbances as determinants of the structure of macroalgal populations and assemblages, and how algal assemblages affect the resilience of coral reefs.

Post-bleaching ecology: Responses of benthic macroalgae to coral bleaching and effects of macroalgae on reef resilience

Coral bleaching is one of the most important causes of coral reef degradation. After bleaching, corals may recover their zooxanthellae and survive, or may die, in which case are rapidly colonised by a diverse assemblage of benthic algae. The type of algal assemblage will be critical to the ability of corals to recover after disturbance (one aspect of resilience) due to the potential of algae to inhibit coral recovery, recruitment, growth and reproduction. Understanding, predicting and managing the consequences of future bleaching events will depend on a better understanding, not only of coral physiology, climatology, and coral recruitment dynamics, but also of algal recruitment dynamics and coral-algal interactions after disturbances.

Coral-macroalgae-herbivore-water quality interactions

Understanding the causes of increases in macroalgal abundance on coral reefs is pivotal for the management of coral reefs.  Reduction in herbivory through overfishing and diseases, increase in nutrient supply through runoff, and coral disturbances (e.g. coral bleaching) are known to promote algal growth and abundance. However, there is little known about the relative roles and interactions of such processes in the recruitment of benthic coral reef algae. Using experimental manipulations of herbivores, nutrients, sediments, algal propagule supply is allowing us a better understanding of the mechanisms leading to algal blooms and phase shifts from corals to algae on coral reefs.


Climate change impacts on coral reef macroalgae

Benthic macroalgae, as corals, are exposed to a variety of global climate stressors. In particularly, crustose calcareous algae (e.g. Porolithon) are conceptually quite vulnerable to increases in Carbon dioxide CO2 and ocean acidification. Given the importance of crustose calcareous algae to coral reef cementation and coral settlement, understanding of the impacts of changing ocean chemistry on calcification of crustose algae will be critical to predict future impacts of global climate change on coral reef communities.

Community ecology, diversity and taxonomy of coral reef macroalgae

Coral reef macroalgae are a very complex and diverse group with a wide variety of forms, sizes, phyla and functional groups. Macroalgal assemblages are highly variable showing temporal, latitudinal, cross-shelf and within-reef variation in composition and abundance. Despite the importance of macroalgae in reef ecology (e.g. primary productivity, reef construction and degradation), there is a critical lack of information on species distributions and diversity. We have carried out macroalgal surveys in remote and coastal coral reefs of the Caribbean, Coral Sea and the Great Barrier Reef to describe the patterns of spatial distribution and temporal dynamics. These studies provide baseline information to understand future changes and impacts of climate change.

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