IASOS Seminar Series
1:15 pm 3 December 2009
Dr John Baxter, Scottish Natural Heritage.
Title: Connecting climate change science with policy - two case studies. The UK Marine Climate Change Impacts Partnership, and The European Project on Ocean Acidification.
Abstract: Dr Baxter will present two case studies of successful climate change science connecting with policy makers: the UK Marine Climate Change Impacts Partnership - a collaborative arrangement between scientists, governments and NGO's to develop a long-term multidisciplinary approach to understanding and communicating the implications of climate change in our seas - and the European Project on Ocean Acidification - a consortium of more than 100 researchers from 27 institutions in 9 European countries - to advance our understanding of the biological, ecological, biogeochemical and societal implications of ocean acidification.
1:15 pm 11 November 2009 - Joint Seminars (Brown and Yoshida)
Matthew Brown, final PhD seminar.
Title: Environmental effects on the growth, maturation and physiology of Antarctic krill over an annual cycle: An experimental approach.
Abstract: Antarctic krill is a keystone species in the Antarctic ecosystem, being a major food source for most Antarctic predators, as well as a target of a substantial fishery. Despite being an integral component in the Southern Ocean, information on growth, maturation and physiology under various light regimes, diet and elevated temperature throughout a full year is limited, hampering understanding of a changing environment on these fundamental factors. This talk will focus on some of my key results on the effects of temperature, light and diet on growth, maturation and physiology of krill. Krill were incubated under controlled feeding and light conditions at three different temperature treatments (-1°C, 1°C and 3°C) over a complete annual cycle (14 months). This is the first study to systematically examine the relationship between key environmental factors and krill life history parameters. One of my major findings from this PhD suggests that krill are possibly governed by endogenous processes, which may be independent of environmental variables.
Toshihiro Yoshida, final PhD seminar
Title: Environmental influences on reproduction in Antarctic krill, Euphausia superba.
Abstract: To be advised.
1:15 pm 30 October 2009
Prof. Andrew Brierley, ANNiMS Visiting Scholar, University of St Andrews, Scotland, UK.
Title: Plankton in a patchy ocean landscape: using active acoustic sampling to explore pelagic ecosystem function and animal behaviour.
Abstract: The open ocean is heterogeneous in space and time. This patchiness has implications across many, if not all, trophic levels - and for fisheries. I will give some examples of our application of acoustic sampling to explore distribution and abundance and behaviour of various animal taxa - from crustaceans to jellyfish - in several marine ecosystems - from the tropics to the poles.
1:15 pm 14 October 2009
Wee Cheah, initial PhD seminar.
Title: Assessing Southern Ocean phytoplankton dynamics and productivity from fast repetition rate fluorometry.
Abstract: The waters of the Southern Ocean are predicted to change in response to climate change. Climate-driven atmospheric and oceanic changes are expected to affect phytoplankton dynamics and productivity in many ways. The fast repetition rate fluorometry (FRRF) technique provides non-destructive, instantaneous measurements of photosynthetic parameters and primary productivity at temporal resolution of seconds. Thus, the FRRF offers in-situ measurement of phytoplankton photosynthesis at a high resolution. A significant linear relationship was observed between the FRRF and traditional radiocarbon-14 estimates (r2 = 0.84, slope = 1.131, p < 0.01) during the 2007 SAZ-Sense expedition. Preliminary results of the phytoplankton photosynthetic parameters measured along the repetitive SR-3 transect line from Tasmania to East Antarctica will be discussed.
2:00 pm 7 October 2009 - PLEASE NOTE STARTING TIME
Cathryn Wynn-Edwards, initial PhD seminar.
Title: CO2-induced effects on phytoplankton, krill nutrition and the Antarctic food web
Abstract: Ocean acidification due to increased levels of atmospheric CO2 is a newly recognized threat to marine ecosystems. The Southern Ocean is one of the most vulnerable regions, due to the increased solubility of CO2 in colder waters and the upwelling of CO2-rich waters in winter. Research into the effects of elevated CO2 on plankton has focussed on a few, predominantly calcifying, taxa from temperate latitudes. Very little is known about the impacts at high latitudes or the flow-on effects for biogeochemistry and trophodynamics. Previous research, however, has reported changes in the composition and nutritional quality of primary producers at high pCO2. This study examines the effects of elevated CO2 on Antarctic primary producers and the ramifications of any changes in their availability and nutritional value for Euphausia superba, the Antarctic krill. Krill are a keystone species in the Antarctic food chain and, with declining catches of other taxa, are potentially a major source of protein in the future. CO2-induced changes in the availability and quality of their food could greatly affect their survival, production and growth in the future. Selected phytoplankton taxa will be grown at a range of CO2 concentrations and their growth, C:N:P, protein, lipid and carbohydrate content and pigment composition determined over a growth cycle. Abundant taxa in the Southern Ocean that are sensitive to pCO2 will then be grown at various CO2 concentrations and fed to krill larvae and adults to determine changes in their survival, growth, grazing, assimilation efficiency, dry mass and nutritional status (C:N:P, protein, carbohydrate, lipid content). Results will provide the first vital insights into the effects of ocean acidification on the trophodynamics in Antarctic waters.
1:15 pm 23 September 2009
Kristen Karsh, final PhD seminar.
Title: Improving the nitrogen isotope record: physiological and environmental controls on nitrogen isotopic fractionation
Abstract: The balance of physical nutrient supply and biological uptake in the surface Southern Ocean plays a key role in setting the air-sea balance of CO2 and global biological production. Nitrogen isotopes record the balance of nutrient supply and removal over time and therefore provide insight into the Southern Ocean's role in past and future climate change. Accurate interpretation of nitrogen isotope data requires knowledge of the magnitude and cause of the isotopic fractionation that occurs as organisms consume nitrate in the surface ocean. This talk focuses on my work to show how marine phytoplankton fractionate nitrogen isotopes at the cellular level when consuming nitrate. One key finding of my research is that light limitation can affect the magnitude of isotopic fractionation, a finding relevant to interpreting nitrogen isotope data from the deep mixed layers of the Subantarctic Southern Ocean. I will also address my work that shows how oxygen isotopes of nitrate are fractionated by marine phytoplankton and how coupled nitrogen and oxygen isotopes of nitrate are proving a powerful tool in studying the modern marine nitrogen cycle.
1:15 pm 16 September 2009 *PLEASE NOTE THIS SEMINAR HAS BEEN CANCELLED*
Cathryn Wynn-Edwards, initial PhD seminar.
Title: CO2-induced effects on phytoplankton, krill nutrition and the Antarctic food web
Abstract: Ocean acidification due to increased levels of atmospheric CO2 is a newly recognized threat to marine ecosystems. The Southern Ocean is one of the most vulnerable regions, due to the increased solubility of CO2in colder waters and the upwelling of CO2-rich waters in winter. Research into the effects of elevated CO2 on plankton has focussed on a few, predominantly calcifying, taxa from temperate latitudes. Very little is known about the impacts at high latitudes or the flow-on effects for biogeochemistry and trophodynamics. Previous research, however, has reported changes in the composition and nutritional quality of primary producers at high pCO2. This study examines the effects of elevated CO2 on Antarctic primary producers and the ramifications of any changes in their availability and nutritional value for Euphausia superba, the Antarctic krill. Krill are a keystone species in the Antarctic food chain and, with declining catches of other taxa, are potentially a major source of protein in the future. CO2-induced changes in the availability and quality of their food could greatly affect their survival, production and growth in the future. Selected phytoplankton taxa will be grown at a range of CO2 concentrations and their growth, C:N:P, protein, lipid and carbohydrate content and pigment composition determined over a growth cycle. Abundant taxa in the Southern Ocean that are sensitive to pCO2 will then be grown at various CO2 concentrations and fed to krill larvae and adults to determine changes in their survival, growth, grazing, assimilation efficiency, dry mass and nutritional status (C:N:P, protein, carbohydrate, lipid content). Results will provide the first vital insights into the effects of ocean acidification on the trophodynamics in Antarctic waters.
1:15 pm 9 September 2009
Tim Ingleton, mid-PhD seminar.
Title: Thermal Plume Impacts: benthic diatoms as bioindicators of a power station cooling field in an estuarine coastal lake
Abstract: Thermal Plume Impacts
1:15 pm 2 September 2009
Amélie Meyer, initial PhD seminar.
Title: Vertical mixing on the Kerguelen Plateau: methods & preliminary results
Supervisors: Helen Phillips (UTAS), Bernadette Sloyan (CMAR), Nathan Bindoff (UTAS).
Abstract: Turbulent mixing and downwelling drive the meridional overturning circulation. The rate at which this mixing takes place greatly affects ocean circulation models. Here we present two techniques that will be used to derive diapycnal mixing estimates using EM-Apex Argo float data from the Kerguelen Plateau in the Southern Ocean. Preliminary results present EM-Apex floats as a great tool to qualitatively and quantitatively study such dynamics.
