Postgraduate Profiles

Alice Gedaria

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Thesis: Microbial trophic interactions and controls on the bloom dynamics of Karlodinium veneficum (syn. Karlodinium micrum) in the Swan River Estuary

The dynamics of Harmful Algal Bloom (HAB) forming species in estuarine and coastal waters are a complex interplay of various physical, biogeochemical and ecological processes. Here we aim to determine the role of microbial food web interactions in the dynamics of HAB species Karlodinium veneficum in Swan River Estuary, Western Australia. This study aims to develop a framework integrating biomolecular properties (DNA, RNA and proteins) of phytoplankton with the hydrodynamic and biogeochemical properties of the estuary while simultaneously looking at the microbial-microalgal interactions. This approach aims to link the cytometric and nutrients data with the physiological properties of the planktonic community in order to examine and better understand the mechanisms for bloom development and decline. Information gathered will be used to develop an improved conceptual ecosystem model of the ‘nutrient flux paths’ within the estuary that is able to resolve the interplay between hydrodynamics and the nutrient cycling dynamics between the different planktonic groups and the water column, across the range of relevant spatial and temporal scales.

Why my research is important

Environmental problems such as Harmful Algal Blooms (HAB) have created a significant negative impact in the aquatic environment and human lives. Despite decades of research in aquatic microbial ecology, nutrient cycling and the dynamics of algal blooms, significant uncertainty remains on the interaction of various physical, chemical and biological components in the aquatic ecosystem.

This study aims to gain an improved mechanistic understanding on how the estuary operates by developing a novel approach that includes biomolecular and cytometric measurement procedures and an integrative theoretical framework that will be used to analyse the dynamics of nutrient flux pathways and how these processes interact with physical processes to control algal species succession and microbial interactions. The research findings will provide a framework to develop potential early warning signals for K. veneficum bloom formation and decline in Swan River Estuary, and the findings may be used to support management activities.