Year 10 Science · Unit 4 · Lesson 12
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Learning Goals
Order the chain
Number these steps of eutrophication from 1 to 5 in the order they happen.
1. Tyre-wear particles from a busy road end up inside mussels in a harbour. Identify the source, the pathway and the receptor, and state whether the source is point or diffuse.
2. A wastewater treatment plant removes most clothing fibres from laundry water. Explain why this does not fully solve the problem of microplastic pollution.
3. At Baiame's Ngunnhu (the Brewarrina fish traps), fish were held alive in stone ponds and each family group was responsible for a particular trap. Explain the ecological understanding shown by each of these two features.
4. NSW fishing rules include bag limits and closed seasons while some species breed. Link each rule to a harvesting principle used by Aboriginal or Torres Strait Islander Peoples.
Wrap Up
Which alternative, reduce, reuse or recycle, would cut microplastic pollution the most? Give one reason.
Order the chain: In the printed order: 5, 1, 3, 2, 4. Nutrients enter → algal growth → decomposition → oxygen depletion → animals suffocate. The oxygen-demanding decomposition step explains the causal link.
Q1 · 3 marks: Source: tyre wear from vehicles (diffuse across the road network). Pathway: runoff/stormwater carries the particles to the harbour. Receptor: mussels take them in while filtering water. Award 1 mark for each source, pathway and receptor; the source mark requires the diffuse classification.
Q2 · 2 marks: Removal does not stop fibres being produced, and some remain in discharged water (1). Captured particles can be transferred to sludge, rather than destroyed; other sources such as road runoff also remain (1). Accept two distinct supported reasons.
Q3 · 4 marks: Keeping fish alive in flowing-water pens reflects understanding that fish need suitable water conditions, so a catch can be held before use (1 explanation + 1 linked feature). Family responsibility creates an accountable group to use and maintain each trap and manage access (1 explanation + 1 linked feature). Do not assume the stem alone proves a quantified conservation benefit.
Q4 · 2 marks: Bag limits relate to limiting how much is harvested so some animals remain (1). Closed breeding seasons relate to timing harvest to protect reproduction and future stocks (1). Accept a correctly explained link to a locally taught seasonal calendar or harvesting protocol; rules and protocols need not be identical.
Source checks: Brewarrina National Heritage listing; CSIRO microplastics research.