Ghedini Projects
Dr Giulia Ghedini
Community Ecology and Evolution Research Group
Giulia.ghedini@monash.edu
Projects
Project offering: Honours/BIO3990/GEN3990
Project title: Assessing how the diversity of phytoplankton communities supports their resilience to global change
Background: Phytoplankton are unicellular algae that drive primary production in the ocean. Their diversity and physiological activity determine how much carbon is taken up from the atmosphere, how much oxygen is produced, and how much energy is transferred to the food web. All these functions are however impacted by global environmental changes.
Project Aims: The goal of the project is to study how the physiological diversity of phytoplankton supports the functioning and resilience of these communities to global change. Using different types of phytoplankton communities, the student will investigate how cells reorganise their physiology and metabolism under stress and the community-level effects of these changes. This project will clarify the cellular responses that help communities buffer change, informing management of aquatic ecosystems and identifying biodiversity aspects critical to resilience.
Techniques: fieldwork – might require going in the water (wading, work from piers, occasional snorkelling), a range of laboratory techniques to characterise phytoplankton, including microscopy, microspectroscopy, respirometry, flowcytometry.
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Project offering: Honours/BIO3990/GEN3990
Project title: How predator alarm cues shape biodiversity effects
Background: Predation is a key process that influences the abundance and activity of species across ecosystems. The fear of being eaten is often sufficient to change how species behave, and even what they look like (think about inducible defences). In the ocean, copepods are the main predators of phytoplankton and the communication between these organisms often occurs through chemical signals: phytoplankton can perceive predators by picking up molecules (alarm cues) that these predators release in the water as part of their normal metabolism. These alarm signals can trigger defenses that reduce, boost, or redirect primary productivity. Since phytoplankton produce over half of the oxygen we breath, understanding the indirect effects of predators on phytoplankton behaviour is very important to model primary production.
Project Aims: The goal of this project is to test how these alarm signals shape the structure and productivity of phytoplankton communities. The student will manipulate the diversity of phytoplankton communities and measure how the presence of copepod alarm cues changes the species composition (biodiversity), oxygen and biomass production of these communities. Depending on how comfortable the student is in the lab, there are opportunities to explore how environmental factors (nutrients or temperature) influence these responses.
Techniques: The student will learn cutting edge techniques in experimental design, concepts in biodiversity theory and predator-prey interactions that can be applied across ecology and evolutionary biology. These include: use of novel equipment to measure metabolism and phenotypes rapidly over many samples, phytoplankton culturing, microscopy, flowcytometry, imageJ, data analyses in R. The student will learn to evaluate and synthetise key concepts in ecology, lead and manage their research project within a collaborative team setting, and position their findings at the forefront of the research area.
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Project offering: Honours/BIO3990/GEN3990
Project title: Assessing the effects of global warming on ocean microbes
Background: In marine ecosystems, phytoplankton are the dominant primary producers. But their activity is strongly affected by interactions with bacteria. Together these microorganisms drive carbon and nutrient cycling, and regulate the productivity and stability of aquatic foodwebs. Phytoplankton-bacteria interactions are diverse, ranging from cooperation to competition, and are often highly specific as certain phytoplankton species are associated with particular bacteria. As the availability of nutrients declines with warming, these interactions might become more negative (competitive), potentially impacting aquatic foodwebs.
Aims: The goal of this project is to 1) establish the specificity of phytoplankton-bacteria associations for phytoplankton strains commonly found in Australia, 2) test how ocean warming will modify these interactions (e.g., cooperation, competition), and 3) the consequences for phytoplankton productivity.
Techniques: The student will learn cutting edge techniques in experimental design and manipulations that can be applied across ecology, evolutionary biology and microbiology. These include: use of novel equipment to measure metabolism and phenotypes rapidly over many samples, phytoplankton culturing, bacterial genome sequencing microscopy, flowcytometry, imageJ, data analyses in R. The student will learn to evaluate and synthetise key concepts in ecology and microbiology, lead and manage their research project within a collaborative team setting, and position their findings at the forefront of the research area.