HR: 1330h
AN: NB33H-04    [Abstracts]
TI: Benthic Algal Production in two Dryland Rivers
AU: * Fellows, C S
EM: C.Fellows@griffith.edu.au
AF: Centre for Riverine Landscapes and Cooperative Research Centre for Freshwater Ecology, Griffith University, Nathan, QLD 4111 Australia
AU: Bunn, S E
EM: S.Bunn@griffith.edu.au
AF: Centre for Riverine Landscapes and Cooperative Research Centre for Freshwater Ecology, Griffith University, Nathan, QLD 4111 Australia
AU: Beard, N J
EM: N.Beard@griffith.edu.au
AF: Centre for Riverine Landscapes and Cooperative Research Centre for Freshwater Ecology, Griffith University, Nathan, QLD 4111 Australia
AU: Thoms, M C
EM: Martin.Thoms@canberra.edu.au
AF: Cooperative Research Centre for Freshwater Ecology, University of Canberra, Belconnen, ACT 2601 Australia
AU: Mesley, E
EM: Edwina.Mesley@canberra.edu.au
AF: Cooperative Research Centre for Freshwater Ecology, University of Canberra, Belconnen, ACT 2601 Australia
AB: In the highly turbid waterholes of dryland rivers in western Queensland, Australia, low light availability restricts benthic algal production to shallow littoral margins. Despite this limited spatial extent, stable isotope work suggests benthic algae are the major source of energy supporting waterhole food webs during periods of low to no flow. We measured benthic community metabolism using in situ chambers in 30 waterholes across the Cooper Creek and Warrego River catchments. Production was measured twice at each waterhole, once within a couple months of a flood and again after an extended period of no flow. Gross primary production in Cooper Creek was greater than that in the Warrego River, with a mean value of 0.46 g C m^-2 day^-1 (SE 0.05 g C m^-2 day^-1) compared to 0.13 g C m^-2 day^-1 (SE 0.02 g C m^-2 day^-1). Rates of production were similar for the two Warrego River trips, but increased considerably after the period of no flow in Cooper Creek. Photic zone depths ranged from 10 to 75 cm, and explained a significant portion of the variation in production. Because waterhole production is a function of the benthic surface area within the photic zone, production between floods will be strongly influenced by interactions between water level changes and waterhole morphology.
DE: 0400 Biogeosciences
DE: 1845 Limnology
DE: 9330 Australia
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly