Summary
In response to several fuel spills on sub-Antarctic Macquarie Island associated with research station operations, the Australian Antarctic Division has initiated a 5-10 year plan to remediate the island’s contaminated sites using low cost in-situ techniques. Methods to enhance the biodegradation of fuel products to non-toxic components, thereby speeding up the process of remediation, are currently under investigation. In addition to manipulating physical variables in soils (through air sparging and nutrient additions), the potential of the sub-Antarctic native tussock grass, Poa foliosa, to assist in the remediation process is being examined. This species has been selected as it is widely distributed in coastal zones on the island and has a deep (~0.5 m) fibrous root system. Growth trials were conducted with seedlings of P. foliosa in soils artificially spiked with SAB (Special Antarctic Blend) diesel at concentrations of 0, 1000, 5000, 10000, 20000 or 40000 mg/kg. Five replicate pots (~1 L) each containing a single seedling were prepared at each concentration and matched with 5 replicate unplanted pots. Pots were kept under controlled growth conditions at 10ºC and plants harvested at 2, 4 and 7 months. The sensitivity of P. foliosa to SAB, and the effect of fuel contaminants on plant health and productivity (photosynthetic activity, pigments and biomass) were assessed. The rate of degradation of soil hydrocarbons and the effect of plants on the health of bacterial communities within the rhizosphere (abundance of total heterotrophs and hydrocarbon degraders and diversity as measured by BIOLOG Ecolplates) were compared in planted versus unplanted pots. This study will determine if rhizoremediaton using P. foliosa will enhance in-situ remediation technologies and promote recovery of a healthy soil environment.