Dr Ron Smernik

Research Interests

Most of my research interests involve organic matter. Brief descriptions of some specific aspects are outlined below. Please contact me if you want to know more about these - or anything else about organic matter.

Sorption of organic chemicals to organic matter.

Organic matter is the most important sorbent phase for non-ionic species in soils and sediments. Sorption to organic matter controls the bioavailability, toxicity and transport of small organic molecules such as hydrocarbons and many pesticides. In most studies, only the amount of organic matter is considered, yet it is known that the nature of the organic matter is also critical. We are addressing this issue by developing new methods that can "see" where in the organic matrix small molecules are sorbed. This approach enables us to test competing theories on the nature of sorption sites (e.g. glassy/rubbery organic matter, hole-filling mechanisms and the role of alkyl and aromatic C). Project funding comes from a 5-year ARC Discovery grant, and is being carried out in collaboration with CSIRO.

The link between chemistry and microbiology in soil carbon cycling.

Although it is well known that rates of organic matter degradation and C cycling in soils are controlled by both the chemistry of the organic matter and the composition of the microbial degrader community, the details of how they interact are poorly understood. In this project we are applying newly developed techniques from the fields of soil chemistry and microbiology to better understand this interaction. Project funding also comes from a 3-year ARC Discovery grant, and is being carried out in collaboration with CSIRO.

Quantification and characterization of black carbon (BC) in the environment.

Black carbon is the residue of incomplete combustion of fossil fuel or vegetation, and includes char and soot. BC is relatively chemically inert in the environment, and this inertness makes it a potentially important carbon sink in both soils and sediments. The trouble is that BC is difficult to quantify – a number of techniques have been developed to do the job, but they give widely varying values, making it virtually impossible to generate reliable estimates of global BC pools, or to understand its movement and fate in the environment. We have developed new NMR-based techniques to measure not only how much BC a sample contains, but also shed light on its composition (BC composition actually varies quite widely). Some of this work is included in the "BC Ring Trial", an international comparison of BC quantification techniques http://www.geo.unizh.ch/phys/bc/ringtrial.html.

Characterization of organic phosphorus.

20-80% of phosphorus (P) in soils is present in the form of organic P. Since inorganic P can get locked up in stable forms that remain unavailable to plants for decades to centuries, the organic P pool has come under scrutiny as a potential source of P for plants. Conventional wisdom has it that much of this organic P is there as phytate - a small, stable, phosphorus-rich molecule found in seeds. However, recent results from our labs have cast doubt on this. We are now seeking to better understand the nature of organic P in soils. This work involves collaborators in NSW and Switzerland.

Chemistry of organic matter in sewage sludge.

Sewage sludge is a rich source of organic matter and is often used as a soil ameliorant. But what happens to this organic matter once in the soil? We have shown using NMR that the organic matter in sewage sludge has a different chemistry to that found in soil, and are using this to trace the fate of sewage sludge amendments. This work involves collaborators in the UK.

Development of NMR techniques.

The research described above utilizes new NMR techniques we have developed specifically for the characterization of organic matter. This is continuing process - each new or improved technique we develop is another tool in the kit-bag.

Publications

2008-2009

Baumann, K., Marschner, P., Smernik, R.J., and Baldock, J.A. Residue chemistry and microbial community structure during decomposition of eucalypt, wheat and vetch residues. Soil Biology and Biochemistry, in press, accepted June 2009.

Gholamalizadeh Ahangar, A., Smernik R.J., Kookana, R.S. and Chittleborough, D.J. (2009). The effect of solvent conditioning on soil organic matter sorption affinity for diuron and phenanthrene. Chemosphere, 76, 1062-1066.

Forouzangohar, M., Cozzolino, D., Kookana, R.S., Smernik, R.J., Forrester, S.T. and Chittleborough, D.J. (2009) Direct comparison between visible near- and mid-infrared spectroscopy for describing diuron sorption in soils. Environmental Science and Technology, 43, 4049-4055.

Hockaday, W.C., Masiello, C.A., Smernik, R.J., Baldock, J.A., Randerson, J.T., Chadwick, O.A. and Harden, J.W. (2009). Measurement of soil carbon oxidation state and oxidative ratio by 13C nuclear magnetic resonance. Journal of Geophysical Research - Biogeosciences, 114, G02014.

Doolette, A.L., Smernik, R.J. and Dougherty, W.J. (2009). Spiking improved solution phosphorus-31 nuclear magnetic resonance identification of soil phosphorus compounds. Soil Science Society of America Journal, 73, 919-927.

Smernik, R. and Skjemstad, J. (2009). Mechanisms of organic matter stabilization and destabilization in soils and sediments: conference introduction. Biogeochemistry, 92, 3-8.

Krull, E., Haynes, D., Lamontagne, S., Gell, P., McKirdy, D., Hancock, G., McGowan, J. and Smernik, R. (2009). Changes in the chemistry of sedimentary organic matter within the Coorong over space and time. Biogeochemistry, 92, 9-25.

Gholamalizadeh Ahangar, A., Smernik R.J., Kookana, R.S. and Chittleborough, D.J. (2009). The effect of lipids on the sorption of non-ionic compounds in soils. Chemosphere, 74, 1062-1068.

Nguyen, B.T., Lehmann, J., Kinyangi, J., Smernik, R. and Engelhard, M.H. (2008). Long-term black carbon dynamics in cultivated soil. Biogeochemistry, 89, 295-308.

Hammes, K., Smernik, R.J., Skjemstad, J.O. and Schmidt, M.W.I. (2008). Characterisation and evaluation of reference materials for black carbon analysis using elemental composition, colour, BET surface area and 13C NMR spectroscopy. Applied Geochemistry, 23, 2113-2122.

Forouzangohar, M., Kookana, R.S., Forrester, S.T., Smernik, R.J. and Chittleborough, D.J. (2008). Mid-infrared spectroscopy and chemometrics to predict diuron sorption coefficients in soils. Environmental Science and Technology, 42, 3283-3288.

Gholamalizadeh Ahangar, A., Smernik, R.J., Kookana, R.S. and Chittleborough, D.J. (2008). Separating the effects of organic matter-mineral interactions and organic matter chemistry on the sorption of diuron and phenanthrene. Chemosphere, 72, 886-890.

Bünemann, E.K., Smernik, R.J., Doolette, A.L., Marschner, P., Stonor, R., Wakelin, S.A. and McNeill, A.M. (2008). Forms of phosphorus in bacteria and fungi isolated from two Australian soils. Soil Biology and Biochemistry, 40, 1908-1915.

Smith, M., Smernik, R.J., Merrington, G. and Tibbett, M. (2008). Changes in sewage sludge carbon forms along a treatment stream. Chemosphere, 72, 981-985.

Bünemann, E.K., Marschner, P., Smernik, R.J., Conyers, M. and McNeill, A.M. (2008). Soil organic phosphorus and microbial community composition as affected by 26 years of different management strategies. Biology and Fertility of Soils, 44, 717-726.

Smernik, R.J., Eckmeier, E. and Schmidt, M.W.I. (2008). Quantitative comparison of solid-state 13C NMR spectra of soil organic matter from an experimental burning site acquired at two field strengths. Australian Journal of Soil Research, 46, 122-127.

Bünemann, E.K., Smernik, R.J., Marschner, P. and McNeill, A.M. (2008). Microbial synthesis of organic and condensed forms of phosphorus in acid and calcareous soils. Soil Biology and Biochemistry, 40, 932-946.

Gholamalizadeh Ahangar, A., Smernik R.J., Kookana, R.S. and Chittleborough, D.J. (2008) Clear effects of soil organic matter chemistry, as determined by NMR spectroscopy, on the sorption of diuron. Chemosphere, 70, 1153-1160.

Hammes, K., Schmidt, M.W.I., Smernik, R.J., Currie, L.A., Ball, W.P., Fukudome, M., Nguyen, T.H., Louchouarn, P., Houel, S., Gustafsson, Ö., Elmquist, M., Cornelissen, G., Skjemstad, J.O., Masiello, C.A., Song, J., Peng, P., Mitra, S., Dunn, J.C., Hatcher, P.G., Hockaday, W.C. Smith, D.M., Hartkopf-Fröder, C., Böhmer, A., Lüer, B., Huebert, B.J., Amelung, W. Brodowski, S., Huang, L., Zhang, W., Gschwend, P.M., Flores-Cervantes, D.X., Largeau, C., Rouzaud, J.-N., Rumpel, C., Guggenberger, G., Kaiser, K., Rodionov, A., Gonzalez-Vila, F.J., Gonzalez-Perez, J.A., de la Rosa, J.M. López-Capél, E., Manning, D.A.C. and Ding, L. (2007). Comparison of quantification methods to measure fire-derived (black/elemental) carbon in soils and sediments using reference materials from soil, water, sediment and the atmosphere- art. no. GB3016. Global Biogeochemical Cycles, 21, B3016 .

Entry last updated: Thursday, 20 Aug 2009