HR: 1330h
AN: B33E-15    [Abstracts]
TI: Soil Microbial Community Contribution to Small Headwater Stream Metabolism.
AU: * Clapcott, J E
EM: Joanne.Clapcott@utas.edu.au
AF: School of Zoology , University of Tasmania Private Bag 5, Hobart, TAS 7001 Australia
AU: Gooderham, J P
EM: flatworm@ozemail.com.au
AF: School of Zoology , University of Tasmania Private Bag 5, Hobart, TAS 7001 Australia
AU: Barmuta, L A
EM: Leon.Barmuta@utas.edu.au
AF: School of Zoology , University of Tasmania Private Bag 5, Hobart, TAS 7001 Australia
AU: Davies, P E
EM: P.E.Davies@utas.edu.au
AF: School of Zoology , University of Tasmania Private Bag 5, Hobart, TAS 7001 Australia
AB: The temporal dynamics of sediment respiration were examined in seven small headwater streams in forested catchments in 2004. A strong seasonal response was observed with higher respiration rates in depositional zones than in gravel runs. The data were also examined in the context of proportional habitat distributions that highlighted the importance of high flow events in shaping whole stream metabolic budgets. This study specifically examines the question of terrestrial soil respiration contribution to whole stream metabolism by the controlled inundation of terrestrial soils. The experiment included six experimentally inundated terrestrial zones, six terrestrial controls, and six in-stream depositional zones. Sediment bacterial respiration was measured using 14C leucine incorporation and cotton strip bioassays were also employed to provide an indicative measure of sediment microbial activity. Despite high variability and exhibiting significantly lower bacterial activity than in-stream sediments, modelling using flow data and habitat mapping illustrated the important contribution of terrestrial soil respiration to the whole stream metabolic budgets of small headwater streams. In addition, microbial community composition examined using phospholipid fatty acid analysis clearly differentiated between terrestrial and aquatic communities. Freshly inundated terrestrial communities remained similar to un-inundated controls after 28 days.
DE: 1806 Chemistry of fresh water
DE: 1845 Limnology
DE: 1860 Runoff and streamflow
SC: Biogeosciences [B]
MN: 2005 Joint Assembly