Maria-Luisa Gutierrez-Zamora

The JAMS rendezvous this October 31st took place in the fourth floor of the Museum with a magnificent view of Sydney, and began with an ad hoc presentation featuring sulphurous scents and sexy fangs. Katherina Petrou (UTS) initiated us in the science of the sulphur cycle in the oceans and how this process is dominated by the production of dimethylsulfoniopropionate (DMSP) by microalgae and its decomposition into dimethylsulphide (DMS), a strong odorous chemoattractant for a range of marine organisms. In tackling the mystery of how harmful algal blooms disappear, Katherina discovered that DMS produced by the dinoflagellate Alexandrium minutum (causative agent of toxic algal blooms) was the chemical cue for the infection of its parasitoid Parvilucifera sinerae.  An elegant video illustrated how DMS at 300 nM was able to activate the parasitoid spores from a dormant state to leave the sporangium (an infected A. minutum cell) in transit to infect other cells and propagate. Activation only occurred in the range of 30 to 300 nM indicating that the effect was dependent on cell density. Thus, Katherina’s work showed that DMS plays an important role in the biological control of toxic algal blooms in the oceans. Her results contribute to the better understanding of marine chemical ecology.

Event Date: 
Wednesday, February 29, 2012 - 18:00 - 18:30
University of Western Sydney

Microbial diversity and ecosystem functions, resilience & recovery: Beyond statistical correlation.


Microbes are the most dominant and diverse group of organisms on planet Earth. They are pivotal to global ecosystem function, carrying out all critical biogeochemical cycling and directly or indirect shape the Earth’s climate. Despite this, their role is not explicitly considered in climate or ecosystem models. This is largely because of their enormous diversity and the lack of theoretical and experimental approaches to illustrate and quantify the magnitude of microbial regulation of ecosystem functions. There are a growing number of studies that provide evidence of the statistical relationship between microbial community and ecosystem function, but such approaches are unable to differentiate between the correlative and casual effects. In this presentation, using a novel diversity dilution approach, I will illustrate the direct role of microbial diversity and community composition in ecosystem function and sustainability, and argue for their explicit inclusion in predictive models.

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