Davis ahoy
 The first view of the Davis coastline |
We arrived at Davis at 3am on Monday 11 January. The station is six hours behind Eastern Standard Time so we began preparing cargo for unloading later in the day and enjoyed the view of the rocky coastline from the ship.
About 20 people will leave the ship to spend the summer at Davis; many of them scientists and diving support personnel working on a range of projects relating to the assessment of the station's sewage outfall site.
Ecotoxicology research
Among the scientists is Kathryn Brown, a first year PhD student from Southern Cross University. Kathryn will be working with the dive team to collect invertebrates such as sea urchins, sea stars, crustaceans and molluscs that live on the sea floor. The animals will be housed in a specially designed aquarium and removed for ecotoxicological experiments.
 Kathryn Brown |
Kathryn will study the impacts of hydrocarbons – from fuel and oil – on the sensitive early life stages (eggs, sperm and larvae) of these Antarctic marine invertebrates. Many Antarctic marine invertebrates keep their young (larvae and juveniles) in brood pouches on their bodies, unlike temperate and tropical species which often release their eggs and sperm into the open ocean. This will make it easier for Kathryn to obtain the early life stages she needs for her experiments.
The young animals will be exposed to different concentrations of three types of fuel commonly used in Antarctica: Special Antarctic Blend, which is used to power Australian Antarctic stations; Marine Gas Oil, a type of diesel often used to power ships; and Intermediate Fuel Oil, a cheaper residual oil (like tar) and diesel mixture also used to power ships.
 The aquarium at Davis |
Kathryn aims to mimic the effect of a fuel spill by mixing these fuels with seawater and then adding different concentrations of the mixture to experimental tanks containing the different invertebrate larvae. She will then assess mortality, behavioural changes and sub-lethal responses in such things as physical development and growth. The aim is to identify the minimum water quality that is needed for invertebrates to reproduce, and to determine trigger values for fuel components to set as targets for the remediation of contaminated marine environments. Kathryn will work closely with another new PhD student from Macquarie University, who is studying how the different hydrocarbons in fuel disperse in cold water and how long they persist. This information will allow her to fine tune her toxicity tests, focusing on hydrocarbons that are most likely to be accessible to the sea floor invertebrates.
Kathryn is excited about extending her skills and experience into Antarctic waters, having just completed an Honours project – for which she won a University Medal – focusing on the fine scale distribution of humpback whales on their southern migration past Cape Byron.
