Physical Sciences and Mathematics Commons^™

Algal Problems Of The Estuary, E. P. Hodgkin, P. B. Birch

Journal of the Department of Agriculture, Western Australia, Series 4

The Peel-Harvey esturine system study began in 1976 because people living near Peel Inlet complained about the accumulation of water weeds and algae on the shores and the smell of hydrogen sulphide (rotton egg gas) that resulted from their decomposition. From 1974 efforts had been made to control this 'algal problem' by raking up the weed with tractors and carting it away. This 'cosmetic activity had little impact on the problem.

The immediate cause was obvious: a carpet of green algae covering about 20square kilometres of the bottom of Peel Inlet. From time to time this 'goat weed' floated to …

Algal Growth And The Phosphorus Cycle, Arthur J. Mccomb, K. S. Hamel, A. L. Huber, D. K. Kidby, R. J. Lukatelich

Journal of the Department of Agriculture, Western Australia, Series 4

Larger algae and microscopic phytoplankton foul the waters of the Peel-Harvey estuarine system, upsetting the fishery and polluting the beaches.

These aquatic plants grow in response to phosphorus runoff from drainage, trapping phosphorus in the estuary and using it in their growth. When they die this phosphorus remains in the system to be recycled for further plant growth.

Algal pollution in the estuary can be lessened by reducing the amount of phosphorus entering the system, increasing phosphorus losses to the ocean, or in some way blocking the trapping and recycling processes.

Modifying Fertiliser Practices, J S. Yeates, D. M. Deeley, M. F. Clarke, D. Allen

Journal of the Department of Agriculture, Western Australia, Series 4

If modified fertiliser practices are adopted phosphorus losses from the Peel-Harvey catchment can be reduced. Farmers can save money on fertiliser applications and the need for more expensive catchment management measures to reduce algal pollution of the estuary will be avoided.

Research data available so far indicate that, with farmer co-operation and the use of the new slow release fertiliser New Coastal Superphosphate, long-term phosphorus application rates can be reduced by 30-40 per cent - and possibly even halved - without lowering agricultural production. This will also reduce phosphorus loss to drainage water.

Although much of the research since 1982 …

Tackling The Problem Off The Farm, C M. Croft

Journal of the Department of Agriculture, Western Australia, Series 4

Methods of redusing phosphorus losses from the catchment soils of the Peel-Harvey esturine system have been discussed in other articles in this Journal.

This article briefly discusses a range of 'off the farm' techniques to improve phosphorus flushing from Peel Inlet or Harvey Estuary to the sea and to treat the phosphorus and the algae. These techniques were among more than 100 management options evaluated by the Peel-Harvey Study Group.

Alternative Land Uses, D A. Morrison, B. C. Mattinson

Journal of the Department of Agriculture, Western Australia, Series 4

One aproach to minimise the high nutrient content and associated algal pollution of the Peel-Harvey estuarine system is to reduce phosphorus losses at their source. Farmers can do this by changing land use is such a way thar phosphorus run-off fromthe catchment soils into drainage is prevented or at least reduced.

The department of Agriculture is investigating the economics of alternative uses, particularly substituting forestry with Pinus pinaster or Eucalyptus globulus (Tasmanian blue gum) for present beef and sheep enterprises. P. pinaster is used for logging and E. globulus for pulping.