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A model to predict the response of the benthic macroalga Spirogyra to reduced base flow in the tropical Australia

Townsend, Simon and Padovan, Anna (2009). A model to predict the response of the benthic macroalga Spirogyra to reduced base flow in the tropical Australia. River Research and Applications: an international journal devoted to river research and management,25(9):1193-1203.

Document type: Journal Article

IRMA ID 75039815xPUB15
Title A model to predict the response of the benthic macroalga Spirogyra to reduced base flow in the tropical Australia
Author Townsend, Simon
Padovan, Anna
Journal Name River Research and Applications: an international journal devoted to river research and management
Publication Date 2009
Volume Number 25
Issue Number 9
ISSN 1535-1459   (check CDU catalogue open catalogue search in new window)
Scopus ID 2-s2.0-70350309335
Start Page 1193
End Page 1203
Total Pages 11
Publisher John Wiley & Sons
Field of Research 0406 - Physical Geography and Environmental Geoscience
0502 - Environmental Science and Management
HERDC Category C1 - Journal Article (DEST)
Abstract A model was developed to predict the impact of reduced dry season base flow, due to groundwater and river extraction, on the standing crop of Spirogyra along an 18 km reach of the Daly River, located in the Australian wet/dry tropics. The alga can constitute up to 40% of the primary producer standing crop and is a food source for turtles. Outputs from a two-dimensional hydrodynamic model and the observed maximum biomass of Spirogyra for a range of shear velocities were used to predict the maximum potential standing crop (MPSC) of Spirogyra. With reduced flow, hydraulic conditions became less favourable for the growth of Spirogyra, whilst the area of suitable substrata was not as responsive. The MPSC of Spirogyra was predicted for the minimum dry season flow for a 47 year period of hydrographic record using two hypothetical extraction scenarios. Both scenarios produced MPSCs that were frequently less than the minimum crop under natural flows and underscored the need for a minimum flow to maintain a MPSC that exceeded the historic minimum. The MPSC, however, is unlikely to be attained due to autogenic sloughing, nutrient supply and other factors, thus the model is best considered an index of the impact of reduced river flows. The model communicates a reduction in the standing crop of Spirogyra due to reduced dry season base flows and an inferred impact on its dependent fauna and the river's nutrient dynamics. The model demonstrates the utility of applying a benthic algal model to evaluate the ecological impact of modified flow regimes and contribute to environmental flow recommendations.
DOI http://dx.doi.org/10.1002/rra.1230   (check subscription with CDU E-Gateway service for CDU Staff and Students  check subscription with CDU E-Gateway in new window)
Additional Notes Early online publication. Update when publication becomes available.
 
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Created: Mon, 27 Apr 2009, 11:06:39 CST by Sarena Wegener