SESE Seminar

Andy Hogg

Fellow, Ocean Modelling, Earth Physics
Research School of Earth Sciences, Australian National University

"Southern Ocean circulation: Wind-driven or buoyancy forced?"

The Southern Ocean is home to the world's strongest and most dynamic ocean current: the Antarctic Circumpolar Current (ACC). The ACC plays a vital role in transporting mass and tracers between the three major ocean basins. Moreover, the Southern Ocean has a strong overturning cell ( that is, upwelling and downwelling) which alters oceanic CO2 uptake and nutrient distribution. The Southern Ocean has a unique set of conditions and driving factors, and the governing dynamics of both the ACC and overturning circulation remain a topic of debate.

The ACC is generally considered to be a wind-driven current. However, recent results indicate that increasing wind forcing does not alter the net transport of water around Antarctica, but instead puts energy into small-scale eddies which mix heat and tracers meridionally. However, wind stress is not necessarily the sole driver of either the ACC or the overturning: it is likely that buoyancy forcing (that is, fresh water flux and heat flux) also contributes to the flow. In this seminar I will review the counter-intuitive dynamical behaviour of the Southern Ocean, and show new results which suggest that buoyancy forcing plays a substantial role in driving the ACC.

4.00 pm Thursday, 26th November 2009

Blakers Lecture Theatre, Mathematics Building

ALL WELCOME

Convenor: Carolyn Oldham (6488 3531)
Host: Greg Ivey (6488 3528)

Martin Fey

Professorial Fellow
School of Earth and Environment

"Soils and restoration ecology: bringing back the biomantle"

Most soils are - or have been - affected by a variety of animals exhibiting a wide range of body size, population and activity. Some animals that lack size often make up for it in numbers. Soil in turn may benefit animals in a variety of ways. It functions as shelter, breeding ground, waste dump, source of food, dietary supplement and means of bodily hygiene. In exploiting soil, animals change it. Mixing, segregation and nutrient cycling take place. The consequences for porosity, aeration, water storage, drainage, density, erodibility and nutrient status can be profoundly important, both ecologically and economically.

Although this talk focuses on examples from Martin Fey's home range, Africa, the principles apply on all continents. Hopefully, in this celebration of the biomantle, there will be something to entertain, inform, inspire new research and serve as a reminder that there is not only life on earth, but in it too.

4.00 pm Thursday, 19th November 2009

Blakers Lecture Theatre, Mathematics Building

ALL WELCOME

Convenor: Carolyn Oldham (6488 3531)
Host: Catherine Rye (6488 1689)

Norman D. Yan

Professor of Biology, York University
Visiting Professor at School of Environmental Systems Engineering

Recovery of Sudbury lakes from acid and metal contamination: local, not regional, processes regulate community re-assembly

Smelters in Sudbury, Canada, were among the world's largest sources of sulphur dioxide and metal emissions, damaging 7000 lakes over a wide region; however, emissions have fallen by 90%, and the atten

tion of ecotoxicologists has turned to questions of what processes regulate ecological recovery. I will present 35 years of water quality and plankton community composition data from four lakes which differ in residual metal contamination, highlighting the surprising result that Middle and Hannah lakes, the smallest lakes, in the most contaminated urban zone, with the highest residual metal levels, are recovering plankton biodiversity more rapidly than more distant lakes with lower metal levels. This was true even though species accumulation curves in Middle and Hannah lakes prove they are receiving fewer colonists than more distant lakes. I will argue that regional processes, i.e. colonist introduction rates, are not regulating recovery. Instead recovery is regulated by colonist establishment success, a local process. I summarize results from bioassays and biotic ligand modelling which prove that colonists can now survive and reproduce in Middle and Hannah lakes, despite their higher metal total metal concentrations. Comparing species sensitivity to water quality would appear to be critical to predicting recovery of plankton species richness. Understanding the roles of regional processes, Allee effects, and community interactions on recovery would appear to be less important.

4.00 pm Thursday, 12th November 2009

Blakers Lecture Theatre, Mathematics Building

ALL WELCOME

Convenor: Carolyn Oldham (6488 3531)
Host: Dani Barrington (6488 8102)

David Sampson

Centre for Microscopy, Characterisation & Analysis, and
Optical+Biomedical Engineering Laboratory
School of Electrical, Electronic, & Computer Engineering,
The University of Western Australia, Australia

Microimaging at The University of Western Australia

The availability of cutting-edge core facilities is becoming an ever more important success factor in high-impact science. Beyond the latest in instrumentation, a key driver of success is high-level academic support of techniques and instruments to ensure their use is part of a vibrant academic interdisciplinary engagement that produces quality outcomes.

The mission of the Centre for Microscopy, Characterisation and Analysis (CMCA) is to support the University of Western Australia's research-intensive function by enabling and facilitating such high-impact research. This mission extends beyond UWA into the local Western Australian, national and international research communities.

In this talk, I will describe the CMCA's facilities in transmission and scanning electron microscopy, including its emerging strength in biological electron microscopy, its ion microprobe facility (NanoSIMS and 1280) which is unique in the world, and its capability in optical and confocal microscopy, automated digital histology, flow cytometry, cell sorting and laser microdissection. I will describe how to access these facilities, and give examples spread widely across the sciences of the outcomes they have helped to achieve. I will describe the CMCA's role in national facilities through its participation in the Australian Microscopy and Microanalysis Research Facility (AMMRF) and describe the framework under which local, national and international access is available to its facilities and a wide range of others within the AMMRF representing the leading edge in characterisation.

Finally, I will touch on what is just over the horizon for the CMCA and how we are planning to get there, including the UWA Bioimaging Initiative, the Western Australian Preclinical Imaging Facility, and performing microscopy in living humans.

4.00 pm Thursday, 5th November 2009

Blakers Lecture Theatre, Mathematics Building

ALL WELCOME

Convenor: Carolyn Oldham (6488 3531)
Host: Catherine Rye (rye@sese.uwa.edu.au)

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