Mrs Athina Puccini1, Dr Mark Farrell1
1CSIRO Agriculture and Food, Urrbrae, Australia
Recent work has clearly established that by looking at the dynamic of climate change, climate gradients, and the vegetation community structure, there are multiple and interactive impacts on Soil Organic Matter (SOM) and the microbial communities living within it. This study examined soil samples taken from 42 sites within a transect that was established under the Terrestrial Ecosystem Research Network (TERN) that runs for 900 km from Cape Jervis in the south to north of the Flinders Ranges in central South Australia. Microbial communities were analysed for community structure using PLFA analysis to provide robust information on functional microbial community structure at time of sampling. Beyond microbial measurements, comprehensive analysis of soil biogeochemistry including litter and soil organic matter chemistry by NMR was conducted. Combined with vegetation community structure and climatic information, this data was then analysed to understand the strengths of relationships between vegetation, climatic, soil and microbial variability along the transect. Litter was more degraded with an increase in rainfall, therefore climate is a major driver and has a significant relationship with litter alkyl/O-alkyl (A/OA) ratio (r = 0.436, P = 0.039). There was also a significant relationship between litter and SOM chemistry (Litter x SOM) (ρ = 0.224, P =0.014) showing a statistically significant relationship between both. In examining relationships between all the variables and the PLFA data, SOM chemistry was most closely related (ρ = 0.447). Further integration of NMR and PLFA data will allow us to link the microbial communities to climate and SOM.
Athina Puccini has 18 years of research laboratory experience in the field of soil biogeochemistry and ecology within CSIROs Agriculture and Food, located on the Waite Campus in Adelaide. She possesses strong analytical capabilities delivering within experimental research projects on SOM characterisation through key analytical expertise in fractionation and NMR. Most recently focussing on the quantification of biomarkers using isotopic GC-MS analysis.