Cambridge International A Level · Marine Science (9693)

Ecological impacts of human activities: Practice Questions

5 multiple-choice questions marked as you go, and 5 written questions with worked solutions. All on Ecological impacts of human activities.

10 questions27 marksFree, no account

Question 1

1 mark

In the context of human impacts on marine ecosystems, what does the term refuse specifically refer to?

Question 2

1 mark

Which strategy would be most effective at specifically limiting the release of primary microplastics into the marine environment?

Question 3

1 mark

A marine food chain is contaminated with Tributyltin (TBT) from antifouling paint. If the concentration in the water is \(1 \text{ unit}\), the concentration in phytoplankton is \(10 \text{ units}\), and the concentration in a predatory gastropod is \(500 \text{ units}\), which statement correctly evaluates these processes?

Question 4

1 mark

According to the syllabus, what is the defining characteristic of secondary microplastics?

Question 5

1 mark

A coastal community implements a strategy to reduce the release of microplastics. Which of the following describes the most likely impact of secondary microplastics on the marine food web?

Question 6

2 marks

According to the syllabus, name the two different sources of toxins that are primarily associated with biomagnification in marine food chains.

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Question 7

3 marks

State two ways in which the discharge of concentrated brine from desalination plants negatively affects the physical and chemical properties of the surrounding benthic environment.

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Question 8

6 marks

In a marine ecosystem, a pesticide concentration increases from \( 0.00001 \text{ mg dm}^{-3} \) in the water to \( 2.5 \text{ mg kg}^{-1} \) in top predators. Distinguish between bioaccumulation and biomagnification to explain these values.

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Question 9

5 marks

Plastic pollution has become a global environmental crisis for marine life.
(a) Describe the environmental factors that contribute to the breakdown of macroplastics into secondary microplastics. [3]
(b) Discuss why the ingestion of microplastics by primary consumers, such as zooplankton, poses a threat to the stability of the entire marine food web. [2]

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Question 10

6 marks

Industrial activities and fishing practices significantly alter marine habitats.
(a) Compare the ecological impacts of dredging and blast fishing on the physical structure of the benthos and the organisms living there. [4]
(b) Explain how the release of untreated sewage into coastal waters leads to the depletion of dissolved oxygen, and describe the effect of this depletion on marine fish species. [2]

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