Question

1. how do pollutants typically affect marine food webs?

a) they improve the health of marine organisms
b) they accumulate in the tissues of organisms
c) they have no impact on the food web
d) they increase the population of primary producers

1. what phenomenon caused by climate change can significantly impact coral reefs?

a) ocean warming
b) decreased nutrient availability
c) increased fish populations
d) lower oxygen levels

1. what is the role of decomposers in a marine food web?

a) to consume primary producers
b) to act as top predators
c) to compete with primary consumers
d) to break down dead organic matter and recycle nutrients

1. in the north sea cod fishery case study, what was a significant effect of the cod population collapse?

a) increased cod reproduction rates
b) decline in smaller fish populations
c) overpopulation of sprat and herring
d) restoration of phytoplankton levels

1. what management strategy was implemented in response to the collapse of the north sea cod fishery?

a) increased fishing quotas
b) closing certain fishing areas
c) allowing unrestricted fishing
d) ignoring the problem entirely

Explanation:

• Question 6: Pollutants like heavy metals or persistent organic pollutants accumulate in organisms' tissues through bioaccumulation and biomagnification in food webs. They harm health (contradicting option a), impact food webs (contradicting option c), and don't increase primary producer populations (contradicting option d).
• Question 7: Ocean warming (option a) causes coral bleaching as corals expel symbiotic algae. Decreased nutrient availability (b) is not a major climate - change - induced impact on corals. Increased fish populations (c) and lower oxygen levels (d) are not the main climate - change - related phenomena harming coral reefs.
• Question 8: Decomposers break down dead organic matter (e.g., dead fish, algae) and recycle nutrients (option d). They don't consume primary producers (a), act as top predators (b), or compete with primary consumers (c).
• Question 9: When cod (a top predator) population collapsed, their prey (smaller fish like sprat and herring) had less predation. This led to overpopulation of sprat and herring (option c), not increased cod reproduction (a), decline in smaller fish (b), or restoration of phytoplankton (d) (as more sprat/herring would consume more phytoplankton).
• Question 10: Closing certain fishing areas (option b) was a management strategy to allow fish populations to recover. Increased fishing quotas (a), unrestricted fishing (c), and ignoring the problem (d) would not help in the recovery of the cod fishery.

Answer:

1. b) They accumulate in the tissues of organisms
2. a) Ocean warming
3. d) To break down dead organic matter and recycle nutrients
4. c) Overpopulation of sprat and herring
5. b) Closing certain fishing areas