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South Africa has a coastline of about 3 650 km - NSC Marine Sciences - Question 3 - 2021 - Paper 1
Question 3
South Africa has a coastline of about 3 650 km. Many different ecosystems are found along this coastline. About 27% are rocky shore, 42% sandy beach and 31% mixed sh... show full transcript
Worked Solution & Example Answer:South Africa has a coastline of about 3 650 km - NSC Marine Sciences - Question 3 - 2021 - Paper 1
Step 1
Sandy beaches are categorised mainly in two groups based on their gradient.
Answer
The gradient of a sandy beach is influenced by the energy of waves and currents. When waves are strong, such as during storms, they lead to a steep gradient as they can carry away sand quickly and deposit it farther up the beach. Conversely, in calmer conditions, weaker waves result in a gentler slope due to the accumulation of sand. Thus, the energy of waves and currents determines how much sediment is removed or deposited, ultimately shaping the beach's gradient.
Step 2
Explain how these snails make use of the tides to get to their food.
Answer
Plough snails utilize the tidal movement to access food sources along the shoreline. As the tide rises, these snails emerge from their burrows to feed on dead organisms at high tide marks. They 'surf' the rising tide to reach feeding areas. Once they have eaten, they retreat back to their burrows as the tide recedes, ensuring their safety and energy efficiency by synchronizing their feeding activities with the natural tidal cycles.