1、Unit 5Marine Disasterso Pre-reading QuestionsoBefore you read the text, take a few minutes to think about the following questions:o1.What marine disasters do you know? Name some of them.o2.What can human beings do to prevent and mitigate these natural disasters?o3. What do you know about algae? Is i

2、t harmful or not？ 1.What marine disasters do you know? Name some of them.o tsunamis, some earthquake, some volcanic eruption, shipwreck, oil spill.2.What can human beings do to prevent and mitigate(緩解） these natural disasters?ocreate awareness of the importance of preventing and mitigating disasters

3、;ogain and store up the knowledge on disaster preventing and mitigating;oraise money for scientific research on disaster warning systems and know more about nature and about the law of nature; omake evacuation plans for governments and local authorities;oacquire surviving and first-aid skills for in

4、dividuals;oprevent from flooding and build dykes (堤壩), dams and reservoirs;othe dams and reservoirs can also be used to fight a drought by allowing the irrigation（灌溉） of dry fields;oprotect our environmentStructure AnalysisoPart 1: General information about “HABs” (Paras.1-3)oSome of phytoplankton a

5、nd cyanobacteria create potent while some of them are harmless.oDifference between HABs and red tide: oRed tide includes blooms discoloring the water but causing no harm; excludes blooms of highly toxic cells but often almost invisible.oTwo mechanisms to cause harm:o1. the production of toxinso2. hi

6、gh biomass accumulationoPart 2: Impacts of HABs (Paras.4-11) oImpacts on human healthoExample : in 1990, six fishermen almost died from eating mussels during a fishing trip.oImpacts on wildlifeoHABs-related animal mortality includes:ofish kill, bird kill, or stranding of manatees and whales.oImpacts

7、 on ecosystemoImpacts include:oloss of shellfish, loss of habitat, sea grass die-back, and altered food web interactions that decease preferred higher tropic level species.oExample: some species cause brown tides.o Two ways that HABs impact ecosystem: the top-down & bottom-upo Impacts on socio-econo

8、myo Reasons for expansion of HABs impacts: n the demand for seafoodn globalization of trade and tourism.o The fields that money is spent to address problems :o public health, commercial fisheries, recreation, tourism, environmental monitoring, and bloom management.o III Vocabulary Studyo A. o 1. ult

9、imately2. inadvertently3. decay4. mechanism5. precaution6. sustain7. recurrent8. teem9. penetration10.contaminateB. o 1. C 2. A 3. A 4. A 5. Bo 6. C 7. A 8. A 9. B 10. Co C. o 1.maintain 2. reserve 3. excluded 4. incur 5. resumeo . Cloze o 1in2transfer3one-month4tourism5reducing6where7portion8rank9p

10、otent10safety11component12Moreover13unknown14estimating15disrupted16alternate17reservation18about19ruined20adverselyV. TranslationoA. o 海洋和淡水中聚集著生命，許多很微小，許多沒有危害；實際上，所有水中生命最后都以這種微小生命為生。盡管大多數浮游生物和藍細菌是無害的，但仍然有一些在特定的情況下會產生毒素。有害藻類通過自身產生毒素或通過聚集大量生物來危害一方，進而影響共生的有機物，從而改變食物網循環。這些影響包括食用海產品或間接暴露于赤潮毒素中而導致的人類疾病和

11、死亡，沿岸居民和漁業的經濟損失，由赤潮導致的魚類、鳥類和哺乳動物的死亡。從人類肉眼來看，有害藻類經常呈現綠色、棕色，甚至紅黃色。不同顏色是由于海藻的種類，水中的生態系統，和有機體的聚集度來決定的。o 藻類泛濫既發生在海水中也發生在淡水中。它主要通過以下兩種方式產生危害。第一種危害是由產生的毒素造成的。毒素直接殺死魚類或貝類,或者人類通過吃受污染的海產品致病。第二種是通過大量生物群聚集，從而造成環境惡化。這些影響具體包括光線變弱，魚鰓結塊，或者是藻類細胞腐爛消耗了過多的氧氣。還有一些有害藻類是因為其物理形狀，它們寄生在魚鰓的組織中，引起魚的生理反應，導致魚的死亡。 oMarine waters

12、teem with microscopic life. Some of them create potent toxins and some of them do harm by accumulating. The algae causing harm is called Harmful Algal Blooms. It not only has impact on health of human beings (such as some known and even unknown diseases), but on wild life as well. In fact, more than

13、 50% of the unusual marine mortality events are now associated with HABs. It is another societal concern that HABs have profound influence on ecosystem. Sometimes, the impact works from bottom up (such as affecting predators and grazing), and sometimes from bottom-up (such as affecting plankton). In

14、 spite of the precautions, the socioeconomic impact is substantial. Many millions of dollars are spent annually addressing the HAB-related problems. The money on public health accounts for the largest part, followed by commercial fisheries and tourism.o Extended Exerciseso 1.feel in the pinko 2.feel

15、ing blue o 3. sing the blues o 4. tickled pink o 5. raises a red flag o 6. yellow journalismo 7. brown as a berryo 8. black sheep o III Vocabulary Studyo A. o 1.pagate3.rupture4.detect5. pensity8.evacuation9.trigger10.disturbanceB. o 1. B 2. A 3. C 4. B 5. Ao 6.

16、C 7. B 8. C 9. B 10. Ao C. o 1.Seismology 2.residence 3.depression 4.generate 5. hydroelectrico . Cloze o 1earthquakes2rarely3awesome4of5occurring6localized7underneath8frequent9margins10at11other12aware13dramatically14coastal15modify16inland17extreme18largest19while20byV. TranslationoA. o 按照是否引發海嘯，地

17、震可分兩類。一是深震（憑經驗，在20公里或12英里以下），隆升通常被表層所吸收，因此不會引發海嘯或只引發小型海嘯。二是淺震（20km以上），由于地表震感強烈，因此也更危險。目前的問題是如何區分這兩種地震。只要有全面的數據，則可較精準地測算出地震的深度。然而，這一過程需花費一定時間。例如，近期日本地震最初深度測算為地下83公里，而最近的一次測算結果卻顯示，深度實為30公里。通常來說，30公里仍可劃入安全等級。但此次地震能量巨大，以往的經驗概不管用。o 新系統的秘密在于地震深度對地震性質的改變不僅僅停留在是否引發海嘯的問題上。巖層斷裂可引發深震，且傳播速度很快大約3公里/秒。而淺震中巖層斷裂傳播速

18、度較慢：一般約1.5公里/秒。速度可能與斷裂巖層的堅硬程度有關，深層巖體受壓力更大，也更堅硬。淺層巖體有韌度，可減緩斷裂。地震學家可據此迅速估算地震深度，如果是海洋地震，還能估算地震是否引發強烈海嘯。oSeismologists have long known that some marine earthquakes generate fierce tsunamis and some do not. The problem is deciding which is which. A new tsunamis-prediction system is under development. It makes an instant estimate of an earthquakes depth through selecting date of propagating speed when rupture occurred in the rock. And thus it can predict the risk of creating a big tsunami. The researchers tried their system out and analyzed many earthquake and predicted some tsunami