Text c. Marine ecology

Exercise 11. Discuss the questions:

1. What is ecosystem? What components and processes does it include?

2. What is the role of biodiversity for ecosystems?

3. How do anthropogenic actions impact ecosystems? Give examples.

to cull – отбраковывать, отстреливать для контроля численности elk, moose – лось bleaching – обесцвечивание кораллов bait – приманка, наживка sea cucumber – голотурия, морской огурец silvertip – белопёрая серая акула grey reef shark – темнопёрая серая акула bycatch – прилов parrotfish – рыба-попугай, скаровая рыба snapper – рифовый окунь seaweed – водоросли to gnaw at smt. – разъедать, обгладывать to smother – подавлять, душить

Exercise 12. Listen to the text (Script 28) which compares two marine ecosystems. Explain how sharks account for the ecological health of coral reefs.

Exercise 13. Put the words in brackets in the correct word form. Listen to the text again to check your answers.

For decades, rangers in Yellowstone National Park, in the American West, had to cull the area's red deer ( (1. know) ___________ locally as elk, though they bear no resemblance to European elk, (2. know) ___________ locally as moose) because the animals' numbers were grazing the place to death and thus (3. threat) ___________ the livelihoods of other species. Many ecologists (4. argue) ___________ that the deer had once been kept under control by wolves, which had been hunted to (5. extinct) ___________ by people. When wolves were (6. introduce) ___________ to Yellowstone, in 1995, these (7. argue) ___________ proved correct. The deer population fell to (8. manage) ___________ levels, and culling stopped. Wolves, it turned out, played a crucial role in (9. keep) ___________ the wider ecosystem intact.

Exercise 14. What information is given in the text about each of the following reef groups? Tick the correct column (sometimes the facts refer to both reef groups).

	the Scott Reefs	the Rowley Shoals
1			are located between Indonesia and Australia.
2			were hit by powerful cyclones and affected by coral bleaching in the mid-1990s.
3			are rich in fish species.
4			are impoverished and demonstrate low species diversity.
5			seem to recover faster from the storms and the bleaching.
6			has been fished for centuries by people interested in catching sharks.
7			are a protected area where all fishing is prohibited.
8			demonstrate three times higher numbers of silvertip and grey reef sharks.
9			are more abundant in midsized predators, like snappers.

Exercise 15. What information does the text provide on:

1. the methods that the team used to obtain data on the reef groups;

2. the fishing methods that are employed;

3. the species diversity and relations of the Scott Reefs;

4. the species diversity and relations of the Rowley Shoals;

5. the impact of top predators – sharks - on the ecosystem of coral reefs?