Ghedini Honours Projects

Dr Giulia Ghedini
Community Ecology and Evolution Research Group
Giulia.ghedini@monash.edu

Projects

Probing the evolution of competitive ability in real time

Background: Biodiversity is shaped by the feedback between ecology and evolution. Ecological interactions influence species evolution and, in turn, rapid evolution can change species interactions. But predicting how species evolve in a community remains difficult. This uncertainty challenges our ability to address the impacts of climate change and biodiversity loss. Our lab has developed experimental setups to study the evolution of species in a community context, offering new opportunities to study evolution between interacting species.

Project Aims: This project will use these new setups to experimentally evolve phytoplankton species with competitors over multiple generations (weeks). The student will track changes in metabolic rates, phenotypic traits (cell size and shape) and population demography to understand how metabolism and life history evolve. The evolved species will then be tested, together or alone, to quantify changes in competitive ability using classic competition frameworks.

Techniques: The student will learn cutting edge techniques in experimental design and evolution 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 evolutionary ecology, lead and manage their research project within a collaborative team setting, and position their findings at the forefront of the research area.

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.

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.