Free Standard AU & NZ Shipping For All Book Orders Over $80!
Register      Login
Marine and Freshwater Research Marine and Freshwater Research Society
Advances in the aquatic sciences
Shopping Cart: ( empty )
You are here: Home > Journals > MF > MF06161
RESEARCH ARTICLE
Contents Vol 58(4)

Potential for algal blooms in tropical rivers of the Northern Territory, Australia

George G. Ganf A C and Naomi Rea B
+ Author Affiliations
- Author Affiliations

A School of Earth and Environmental Sciences, The University of Adelaide, Adelaide, SA 5005, Australia.

B School of Australian Indigenous Knowledge Systems, Charles Darwin University, Darwin, NT 0909, Australia.

C Corresponding author. Email: george.ganf@adelaide.edu.au

Marine and Freshwater Research 58(4) 315-326 https://doi.org/10.1071/MF06161
Submitted: 6 September 2006  Accepted: 15 January 2007   Published: 16 April 2007

Abstract

Rivers in the Northern Territory (NT) of Australia are under pressure from increasing vegetation clearance, land use and nutrient run-off. The literature on algal blooms clearly identifies the predisposing factors but in the NT, these factors are not well researched. We report on the potential for tropical rivers to experience problems related to algal growth. NT rivers were found to have a low nutrient status and a viable inoculum of blue-green, brown and green algal communities. The growth response of these algal groups to nutrient enrichment via bioassays and pulse-amplitude-modulation (PAM) fluorometry measurements varied among rivers and the addition of N, P or N&P. However, the overwhelming findings were that all rivers had the potential to experience algal blooms with enrichment. Back-calculations based on the chlorophyll concentrations recorded in bioassay experiments and stoichiometric ratios of chlorophyll:nutrients suggest there are pools of biologically available organic forms of N and P in addition to inorganic forms. The role of river length in the development of algal blooms was investigated: the longer the river reach, the slower the flow, and the greater the availability of nutrients, the higher potential for algal blooms. Given the strong indications that increased nutrient run-off to tropical rivers will result in algal blooms, prudent land-use and development with nutrient management strategies is essential.

Additional keywords: biologically available nutrients, cyanobacteria, discharge, river length, stoichiometry.


Acknowledgements

Financial support from Land and Water Australia is gratefully acknowledged. The Environmental Research Institute of the Supervising Scientist provided generous laboratory accommodation. G.G.G. was supported by the University of Adelaide Special Studies Program. Dr. Justin Brookes provided helpful comments on the manuscript.


References

Australian and New Zealand Guidelines for Fresh and Marine Water Quality (2000). ‘Australian and New Zealand Environment and Conservation Council (ANZECC) and Agriculture and Resource Management Council of Australia and New Zealand (ARMCANZ) Paper No. 4. Vol. 1.’ (Department of Environment and Heritage: Canberra.)

Barranguet, C. , van Beusekom, S. A. M. , Veuger, B. , Neu, T. R. , Mandiers, E. M. M. , Sinke, J. J. , and Admiraal, W. (2004). Studying undisturbed autotrophic biofilms: still a technical challenge. Aquatic Microbial Ecology 34, 1–9.
Burch M. D., Baker P. D., Steffensen D. A., Bursill D. B., Bain D. B., Ganf G. G., and Brookes J. D. (1994). Critical flow and blooms of the cyanobacterium Anabaena in the River Murray South Australia. In ‘Proceedings of Environmental Flows Seminar, Canberra, 25–26 August 1994’. pp. 44–51. (Australian Water and Wastewater Association: Antarmon, NSW.)

Dillon, P. J. , and Rigler, F. H. (1974). The phosphorus-chlorophyll relationship in lakes. Limnology and Oceanography 19, 767–773.
Harris G. P. (2001). ‘A Nutrient Dynamics Model for Australian waterways: Land Use, Catchment Biogeochemistry and Water Quality in Australian Rivers, Lakes and Estuaries.’ Australia State of the Environment Second Technical Paper Series (Inland Waters). (Department of the Environment and Heritage: Canberra.)

Hart, B. T. (2004). Environmental risks associated with new irrigation schemes in Northern Australia. Ecological Management & Restoration 5, 106–110.
| Crossref | GoogleScholarGoogle Scholar | Oliver R. L., and Ganf G. G. (2000). Freshwater blooms. In ‘The Ecology of Cyanobacteria’. (Eds B. A. Whitton and M. Potts.) pp. 149–194. (Kluwer Academic Publishers: Dordrecht.)

Pusey, B. J. , and Arthington, A. H. (2003). Importance of the riparian zone to the conservation and management of freshwater fish: a review. Marine and Freshwater Research 54, 1–16.
| Crossref | GoogleScholarGoogle Scholar | Queensland Environmental Protection Agency (2006). Queensland Water Quality Guidelines. (Environmental Protection Agency: Brisbane.)

Rea N., Dostine P. L., Cook S., Webster I., and Williams D. (2003). ‘Environmental Water Requirements of Vallisneria nana in the Daly River, Northern Territory.’ Report No. 35/2002. (Department of the Environment and Heritage: Canberra.)

Reynolds, C. S. , and Maberly, S. C. (2002). A simple method for approximating the supportive capacities and metabolic constraints in lakes and reservoirs. Freshwater Biology 47, 1183–1188.
| Crossref | GoogleScholarGoogle Scholar | Talling J. F., and Driver D. (1963). Some problems with the estimation of chlorophyll a in phytoplankton. In ‘Proceedings of the Conference of Primary Productivity Measurements, Marine and Freshwater, 1961, University of Hawaii.’ (Ed. M. Doty.) pp. 142–146. (US Atomic Energy Commission TID-7633: Washington, DC.)

Townsend, S. A. (2000). Seasonal pattern and inferred phosphorus limitation of phytoplankton biomass in two tropical reservoirs in northern Australia. Marine and Freshwater Research 51, 91–96.
| Crossref | GoogleScholarGoogle Scholar | Webber E. J. (2000). Responses of Mary River Phytoplankton to Nitrogen and Phosphorus Enrichment. BSc Honours Thesis, Northern Territory University, Darwin.

Webster, I. , Rea, N. , Dostine, P. , Padovan, A. , Townsend, S. , and Cook, S. (2005). An analysis of primary production in the Daly River, a relatively unimpacted tropical river in northern Australia. Marine and Freshwater Research 56, 303–316.
| Crossref | GoogleScholarGoogle Scholar | Wright R. (2004). ‘A Short History of Progress: 2004 Massey Lecture (Ideas).’ (House of Anansi Press: Toronto.)