Вы услышите интервью с ученым. В следующих заданиях выберите правильный ответ.
1. Fish reactions are affected by
1) the changing amount of oxygen.
2) carbon dioxide.
3) carbonic acid.
2. Which sense is not used by young fish to seek new habitat?
1) Sense of smell.
2) Sense of sight.
3) Sense of hearing.
3. Scientists have chosen clown fish for their experiments because they
1) can be bred in captivity.
2) are similar to Nemo.
3) live in the waters of the Great Barrier Reef.
4. During the experiments the treatments of water were based on
1) today’s C02 environment.
2) different C02 environments.
3) predictions for the C02 environments later in the century.
5. In the environment with the normal level of C02 fish usually
1) show no preference for any direction.
2) move towards the speaker.
3) move away from the speaker.
6. What is the most probable explanation for the unusual behaviour of fish under high levels of C02?
1) They have lost their natural avoidance behaviour.
2) They have gone deaf.
3) Their hearing has been impacted on.
7. The scientists are not sure whether the impact of high C02 levels
1) is detrimental to fish.
2) will be seen in all fish species.
3) is necessary to study.
1 – 3
2 – 2
3 – 1
4 – 2
5 – 3
6 – 3
7 – 2
Interviewer: It is a proven fact that if you elevate the amount of carbon dioxide in the atmosphere, this will have the effect of acidifying the sea, because carbon dioxide, when it dissolves, forms carbonic acid. This acidification, notwithstanding the invariable amount of dissolved oxygen, can change the way that fish react to the world around them. Dr Steve Simpson, who’s from Bristol University, has been looking at how this affects their ability to sense the sound of danger.
Dr. Simpson: My research has focused on the behaviour that coral reef fish show when they’re looking to seek habitat after a period of a few days of developing out at sea in the plankton. My interest has been particularly on the importance of auditory cues, which are sounds produced by animals on the coral reef that the small fish can detect and use to pick specific habitats. Recent research has demonstrated that fish which experience ocean acidification lose their natural sense of smell, which is the other cue that fish use to detect reef habitat. So the question is whether the sense of hearing is unaffected by ocean acidification and so, will be able to compensate for this loss of sense of smell, or whether hearing is also impacted on by ocean acidification.
Interviewer: So what was the experimental technique? What did you actually do and what fish did you test?
Dr. Simpson: We worked with clown fish. Clown fish are similar to Nemo, and are readily available through the aquarium trade. Clown fish are native to warmer waters of the Indian and Pacific oceans, including the Great Barrier Reef but they can be bred in captivity. So for scientists, this is great because it means that we can actually work with the embryos of these fish. So we took embryonic clown fish and put them into different treatments of water that were either based on today’s C02 environment, or based on different predictions, for the C02 environments later in the century. Then we took the fish and put them into a long tube facing towards a speaker and we allowed the fish to move around in this tube while we played sounds to them and monitored their behaviour.
Interviewer: What did the fish do under those circumstances when you played the sounds of a reef?
Dr. Simpson: We used a recording of daytime coral reef noise, and in the natural environment fish normally move away from this sound. A coral reef is a dangerous place during the daytime because of the high density of predators. And so, the noise of all these predators causes fish naturally to move away from the sound. On the contrary, the fish that had experienced high levels or elevated levels of C02 showed no response to the recordings. So they were equally spending time moving towards the speaker as well as away from it.
Interviewer: Gosh! So that’s quite striking, isn’t it? Have you any clue as to why they behave like that?
Dr. Simpson: It’s certainly possible that the fish have gone deaf or it may be that the fish can hear these sounds quite well but lose their natural avoidance behaviour. But it’s most likely that their hearing has been partly influenced by the environment because we did look at the growth of their ear bone, which is a central part of a fish ear, and we found there are differences in the shape or the size of the ear bone between the fish from different treatments. Either way, any of those three scenarios would be bad news for the fish in the natural environment.
Interviewer: And what do you think the implications are for what you’ve found?
Dr. Simpson: Well, the implications are that loss of hearing or their natural responses to sound are certainly detrimental to fish, because fish live in a very auditory world, and sounds are important for detecting and avoiding predators, and also for detecting potential prey items. So there would be fairly detrimental impacts on fish populations. We don’t know whether this impact would be seen across the board in terms of different fish species and that’s the focus of our research now. It is also necessary to study whether fish can adapt to C02 levels because there can be some rare fish that already have more tolerance that will then be able to keep pace with the change.