Job Post: Two Postdoctoral Positions in Australia with Ian Anderson and Jeff Powell

Ref 114/13 Postdoctoral Research Fellow in Eucalypt – Fungal Associations, Hawkesbury Institute for the Enivronment 

For a position description and application instructions, go to: 

http://bit.ly/XJzE0D

This is an exciting opportunity to undertake research related to an Australian Research Council Discovery (ARCD) grant (‘Switching partners: a driving force for tree productivity in a changing environment?’). Many eucalypts form mycorrhizal associations with two different and diverse groups of fungi, a trait shared by only a few ecologically and economically significant tree species. While each of these groups of fungi are important contributors to global primary productivity, the benefits that trees derive from these dual associations are not fully known. This research will explain the basis for this diversity and determine whether trees will make greater demands of their partners in future climates.

Applicants should have expertise within the broad areas of plant-microbe associations, molecular microbial ecology, soil science, or related fields. A background in the generation and analysis of next-generation sequence data will also be well regarded.

This is a full time, fixed term (2.5 years) appointment based at our Hawkesbury campus.

Remuneration Package: Academic Level A $91,289 to $96,851 p.a. (comprising Salary $77,140 to $81,840 p.a., plus 17% Superannuation and Leave Loading).

Position Enquiries: Dr Jeff Powell, +61 (0) 2 4570 1093 jeff.powell@uws.edu.au
Closing Date: 21 March 2013

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Ref 161/13 Postdoctoral Research Fellow in Plant-Fungal Associations, Hawkesbury Institute for the Environment

For a position description and application instructions, go to:  

http://bit.ly/XlK7mL

This is an exciting opportunity to undertake research related to an Australian Research Council Discovery (ARCD) grant (Plant : fungal symbioses in Australian forests – new perspectives using laser microdissection). The main goal of this project is to understand the importance of interactions between basidiomycete fungi and the roots of understorey Ericaceae shrubs, and determine the potential for these fungi to form mycelial linkages between the understorey shrubs and overstorey trees in Australian forests.

The successful applicant will have experience in the use of microscopy and/or molecular microbial ecology technigues in studying plant:microbe associations.

This is a full time, fixed term (2 years) appointment based at our HAwkesbury campus.

Remuneration Package: Academic Level A $91,289 to $96,851 p.a. (comprising Salary $77,140 to $81,840 p.a., plus 17% Superannuation and Leave Loading).

Position Enquiries: Professor Ian Anderson, Director of Research, +61 (0) 4570 1993 or  i.anderson@uws.edu.au
Closing Date: 21 March 2013

Cool toys = Hot data? (part 1)

As part of our work on a the SPRUCE experiment, we have been quantifying the various microbial activities in a peat bog in MN. We have also been lucky enough to explore some new approaches to improve our research methods as part of this. Two of these efforts involve some pretty cool science ‘toys’. Im going to discuss one below, and save the other for a future post.

One of the ways we are trying to accomplish the above, is to understand more thoroughly how the enzyme activities of microorganisms may vary in response to a range of temperatures. These enzyme potential analyses have been around for years and allow us to understand how microbial activity contributes to the cycling of carbon and nutrients under various specific stimuli. These work are possible now, thanks to work in the past by Bob Sinsabaugh, Don Zak, and many others. We accomplish this by adding peat (or soil) to mixtures that contain a fluorescent dye labeled substrate compound, that the enzymes the microorganisms secrete into the soil (or peat) can breakdown. When the fluorescent label is liberated from the the substrate compound, it fluoresces, and we can quantify it. If we want to quantify this response over a range of temperatures, it usually involves hunting up a host of large incubators in which to do the studies. At most usually 4 or 5 of these are available at any given time. Last month, Meg Steinweg and I visited the lab of collaborator Joel Kostka at Georgia Tech that had a cool toy that allowed us to do this much more efficiently.

This is a gradient heat block (much like those used for PCR, but bigger) that allowed us to fairly precisely conduct our experiments. It is a custom designed tool that was machined from a block of solid aluminum, and has an electric heater attached on the high temperature end, as well as ports that allow circulation of a chilled glycol solution on the low temperature end. To this they added holes at an even spacing that we can add test tubes too. This creates a precise gradient of temperatures over a range of about 0 to 40 degrees Celsius (~32 to 104 degrees Fahrenheit) to do our enzyme assays. Once we set the temperature, this gradient was repeatable each day as seen below (there are three separate measurements in the graph, taken over two days, that largely overlap!)

This science ‘toy’ is translating to some really cool data sets for our SPRUCE projet. In SPRUCE we will be using a belowground heating system to warm up the peat in the bog to understand how all the carbon stored in the peat will respond (a paper on this technology is here). This could have implications for the potential of future climate change to feedback and cause additional releases of carbon dioxide and methane to the atmosphere from bogs and other ecosystems. To get an initial handle on this in laboratory experiments, we used the ‘toy’ above to look at three different microbial enzyme responses tied to carbon, nitrogen and phosphorus cycling using peat collected from Minnesota at different times of the year. Typically we would expect responses leading to a rather smooth exponential curve showing increased activity with increased temperature (up to the point where the enzymes become denatured and activity drops off). Somewhat surprisingly, Meg’s work using this tool, looks to be showing two different responses in at least some samples. In an example of one of our Beta-Galactosidase activity assays below, we see a linear response at lower temperatures (below about 15C), and what seems to be a separate linear response at higher temperatures (above about 15C), instead of the expected exponential curve. While this graph is only showing a set of data originating from one peat sample, for one enzyme activity, collected at one time of year… When we look at a range of such samples, Meg’s data is showing trends that vary by depth in the peat, and time of year the samples were taken.

Im not sure exactly how these data should be interpreted yet (we need more of them of course), but what it could suggest, is that what we are seeing is enzyme responses from multiple communities of microorganisms, that exist separated by space (depth in the peat) and time (season in which the samples are collected). That would be pretty cool to prove, as it might effect the interpretation of the seasonal responses we will see in Minnesota when we heat up the bog. This is not unprecedented, as we saw similar phenomena when I was studying alpine tundra communities in Colorado during graduate school. However, this could justify more winter trips to MN, which believe it or not, I enjoy!

We have recently began some work collaborating with a group that does sensor development at ORNL, that is related to the SPRUCE project objectives. Hopefully in the near future I will be able to blog about it as well. However, as of now, while im convinced we are producing some really cool toys, the project has yet to produce enough cool data. Hopefully the data arrives soon!