Human Impacts on the Intertidal Wetlands of Homebush Bay

1. Human Impacts on the Intertidal Wetlands of Homebush Bay

2. Lithosphere • Atmosphere • Hydrosphere • Biosphere

3. Human impacts and the four components of the biophysical environment Atmosphere • Changing of wind patterns caused by inappropriate location and design of buildings (wind channelling effects) • Hydrogen sulphide produced by waterlogged soils is a feature of this ecosystem. Processes within the soil may be disrupted by construction activities Hydrosphere • Modifications to the hydrosphere e.g. straightening of Powells Creek alters levels of dissolved oxygen. • Increased levels of turbidity and toxic chemicals because of urban and industrial landuses • Oil spills from vessels in Sydney Harbour Lithosphere • Construction of bund walls changed the hydrology of the site by reducing and redirecting the flow of water, thereby affecting soil moisture for the mangroves. • This affects the health of the mangroves and the decomposer organisms that recycle minerals essential for the ecosystem functioning Biosphere • Atmospheric gases necessary for plant and animal growth may be altered by pollution • The death of marine organisms due to dumping of toxic chemicals • Construction of rock and dirt bund walls introduces weeds into the ecosystem

6. An example of bund walls

7. Activities • Answer questions 1-3, p105. • Explain how the use of intertidal wetland ecosystems by humans can be describes by degrees of modification to natural vegetation • Identify the five management issues affecting the Bicentennial Park intertidal wetlands