The relative importance of shading and nutrients on algal production in subtropical streams
Article first published online: 7 JUL 2008
Volume 46, Issue 9, pages 1269–1278, September 2001
How to Cite
Mosisch, T. D. , Bunn, S. E. and Davies, P. M. (2001), The relative importance of shading and nutrients on algal production in subtropical streams. Freshwater Biology, 46: 1269–1278. doi: 10.1046/j.1365-2427.2001.00747.x
- Issue published online: 7 JUL 2008
- Article first published online: 7 JUL 2008
- algal production;
1. We used artificial substrata in forested and open streams in South-East Queensland, Australia, to determine the relative importance of shading from riparian vegetation and of nutrients on periphyton growth, and whether nitrogen and/or phosphorus limited algal productivity.
2. Nutrient-diffusing substrata consisting of agar enriched with N, P and N + P, and controls without nutrients, were deployed in duplicate at 15 sites in headwater streams with riparian canopy cover ranging from 0 to 88%.
3. Shading was the over-riding factor controlling periphyton biomass accrual on the artificial substrata, with nutrients playing a relatively minor role. Microscopic examination of periphyton scrapings taken after 7 weeks revealed that diatoms dominated on the artificial substrata in shaded streams, whereas filamentous green algae dominated the algal assemblage in the more open canopy streams.
4. Whilst nutrients had little effect on the accrual of algal biomass compared with riparian shading, there was evidence that nitrogen, and not phosphorus, stimulated periphyton production in streams with sufficient light.