TPO-27-L1

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TPO 27 Coral Reefs Marine

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What is the lecture mainly about?
  • A . The transplantation of young coral to new reef sites.

  • B . Efforts to improve the chances of survival of coral reefs.

  • C . The effects of temperature change on coral reefs.

  • D . Confirming the reasons behind the decline of coral reefs.

显示答案 正确答案: B
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    Listen to part of a lecture in a marine biology class.
    So we have been fairly thorough in our discussion about coral reefs, which of course are prominent, oceanic features made of hard limestone skeletons produced by tiny coral animals. We've gone over where coral reefs are usually formed - along the edges of shallow ocean banks in tropical or subtropical regions, and the fact that they are declining at an alarming rate. But I don't want to leave you with the impression that all is lost. There are several techniques being employed today that could prove useful in assuring the future of the reefs.
    Now, we've talked in depth about coral bleaching, or whitening, which as you recall, is a symptom of...well that the coral is suffering.As you know, coral is very sensitive to water temperature.Even though one or two degree Celsius rise in sea surface temperature for a relatively short amount of time can cause bleaching. Recently, researchers have used data collected by monitoring surface water temperatures to improve the ability of a reef to recover from bleaching.One future possibility is that improved monitoring can help predict where and when bleaching will occur, which might potentially enable us to mitigate its effects.
    And there's another technique that's been experimented with to try to help coral reefs recover from bleaching.It's called coral transplantation.This involves moving young coral from a healthy reef onto a degraded reef, you know, in an attempt to regenerate the degraded reef by encouraging young healthy coral to take over. There has been some success with this, but it's still somewhat controversial. Some scientists support it because, well for one thing, it means you don't have to rely on the existing coral to reestablish itself because it might not be able to. But in my opinion, transplanting coral should only be used as... well as a last resort. I mean, this method is not only costly but it's... well even if it's successful, it still fails to address the ongoing problem, the root causes of the degradation, which really is paramount to devising an effective solution.So I don't really take comfort in the successes they have had with transplantation.
    Perhaps some more constructive use of our time could be spent at researching corals that do survive, like in areas known as refugia.Refugia are areas on the reef that are seemingly, well resistant to bleaching. See, when coral reefs experience bleaching, it's rarely a case of the whole reef being affected.There are almost always pockets of coral on the reefs that remain unaffected.And these are often the lower areas of the reef, those located in deeper water, where temperatures are lower.
    Now, we have evidence that corals in these locations are able to escape the destructive bleaching that affects portions of the reef in shallower or warmer water. So in my mind, it's these refugia that are the key components of overall reef resilience. These should be the area of concentration for researchers to locate and protect those regions as a way to sustain coral reefs.
    And we can also protect the reefs by protecting the surrounding ecosystems, like mangrove forests and seagrass beds.Both of these grow in coastal waters, often in the vicinity of coral reefs. By protecting these areas, we also protect the coral. Let's take, for example, the mangrove forests.Mangrove root systems have the ability to absorb and well trap sediments and pollutants in water that flows through them before they enter the ocean. This of course has beneficial results for the nearby coral reefs.
    And fishery's management is another key strategy. Overfishing can be seriously disruptive to coral.Let me give you a couple of examples. Overfishing certain species of fish and shellfish like snappers, barracudas and even lobsters. Well all of these creatures feed on snails, worms and other organisms that eat coral. So depleting the number of lobsters, for example, means that we are adding to the threat of coral decline. Sea urchins are another example. They eat algae and prevent it from overwhelming the coral.Since the disappearance of sea urchins from the waters up the coast of South Florida, many coral reefs there have been smothered by the uncontrolled growth of algae.

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    听一段海洋生物学课程上的演讲
    我们已经十分全面的讨论了珊瑚礁,珊瑚礁是主要的海洋生物由小珊瑚动物产生的硬石灰石骨骼构成。我们已经讲了珊瑚礁的通常形成地——沿着热带或者亚热带浅海岸边缘。事实是,他们在以惊人的速度减少。但是我不想给你们留下印象说所有珊瑚都消失了。现在我们应用若干经证明有效的技术确保珊瑚礁的未来。
    我们已经深入讨论了珊瑚白化或者变白,你们记得,是一个症状……珊瑚在遭受折磨。正如你们所知,珊瑚对水温非常敏感。即使一摄氏度或者两摄氏度较短时间的海水表面温度上升会引发珊瑚白化。最近,研究人员使用通过监测表面水温度得到的数据提高珊瑚礁从珊瑚白化中恢复的能力。未来有一种可能,改善后的监测可以帮助我们预测白化发生的时间和地点,这可能让我们有能力减弱白化对珊瑚的影响。
    还有另一个实验技术试图帮助珊瑚礁从白化中恢复。这个技术叫做珊瑚移植珊瑚移植是把健康珊瑚礁的珊瑚虫移动到退化的珊瑚礁上,通过鼓励年轻健康的珊瑚虫接管来使退化的珊瑚礁再生。珊瑚移植已经取得了一些成功,但是这个方法仍有争议。一些科学家支持移植因为一方面这意味着你不是必须依赖老的存在的珊瑚虫去重建自己因为很可能它们没有重建的能力。但是在我看来,珊瑚移植应该只被用作最后的手段。我的意思是,这个方法不止成本高同时,即使移植成功,也不能成功解决正在发生的问题,解决退化的根本原因对于想出一个有效的解决方法是最重要的。所以,当我们在移植上取得成功我不感到安慰。
    可能更有建设性利用时间是去研究存活下来的珊瑚,比如残遗种保护区。残遗种保护区是珊瑚礁上的区域,看起来能很好地抵御白化。当珊瑚礁经历白化时,很少有珊瑚整体被影响的案例。珊瑚礁上总是有珊瑚虫可以不被影响。这些常常是珊瑚位置较低的部分,位于温度较低的深水中。
    现在,我们有证据证明这些位置的珊瑚能够逃脱对较浅或者较温暖水中起毁灭影响的白化。所以,在我看来,残遗种保护区才是珊瑚整体恢复的关键部分。残遗种保护区才应该是研究者们关注的区域,研究者们应该定位并且保护这些区域作为维持珊瑚的一种方法。
    我们也可以通过保护其周边的生态环境保护珊瑚,比如红树林和海草床。这些都生长在沿岸水域中,常在珊瑚礁附近。通过保护这些区域,我们也可以保护珊瑚。我们以红树林为例。红树林的树根系统能在水进入海洋之前吸收和捕获流水中沉积物和污染物的能力这对周围的珊瑚很有好处。
    渔业管业是另一个关键策略。过度捕鱼会严重破坏珊瑚。我来举几个例子。过度捕捞特定种类的鱼和贝壳类海洋生物,比如鲷鱼,梭鱼甚至龙虾。这些生物全部以蜗牛,虫子和其他吃珊瑚虫的生物为食。所以,打个比方,捞尽龙虾的数量意味着我们增加了珊瑚减少的威胁。另一个例子是海胆。海胆吃海藻并且预防海藻覆盖珊瑚。由于南佛罗里达沿岸海水中海胆的消失,那里的很多珊瑚都因为海藻不受控制的增长窒息而死。

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There are several techniques being employed tody that could prove useful ensuring the future of the reefs.
这就是 lecture 的 topic sentence 根据他来确定选项。

当前解析由chien提供

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