科技英语海洋死区精.ppt

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1、科技英语海洋死区第1页，本讲稿共14页Thats bad news for fish and for the people who eat Thats bad news for fish and for the people who eat them.Much of the worlds fish supply is already them.Much of the worlds fish supply is already troubled due to overfishing,dying reefs and the troubled due to overfishing,dying ree

2、fs and the disappearance of marshland,mangrove forests(disappearance of marshland,mangrove forests(红树林红树林)and other coastal environments that serve as)and other coastal environments that serve as breeding grounds and nurseries for many valuable breeding grounds and nurseries for many valuable specie

3、s.species.Biologists havent been able to figure out Biologists havent been able to figure out how much oxygen depletion(how much oxygen depletion(减少减少)alone)alone contributes to the decline of teetering(contributes to the decline of teetering(摇摇欲坠摇摇欲坠)fisheries the question is hotly debated in marin

4、e-fisheries the question is hotly debated in marine-science circles these days but few experts would science circles these days but few experts would disagree that an increase in dead zones can only be a disagree that an increase in dead zones can only be a detrimentdetriment(损害损害).).第2页，本讲稿共14页科学家注

5、意到，在过去的二三十年里，大片的沿海水域科学家注意到，在过去的二三十年里，大片的沿海水域变成了海洋死区变成了海洋死区一大片的海底因为海水中的氧气缺一大片的海底因为海水中的氧气缺乏，几乎很少有生物能够在那生存。乏，几乎很少有生物能够在那生存。20042004年，联合国环年，联合国环境署对这一现象做出评估，认为海洋死区主要是由境署对这一现象做出评估，认为海洋死区主要是由于农业排放的污染物所致，并宣称海洋死区是于农业排放的污染物所致，并宣称海洋死区是2121世世纪最严重的环境问题。两年后，联合国环境署注意到被纪最严重的环境问题。两年后，联合国环境署注意到被认定的死区数量已经从认定的死区数量已经从15

6、0150块上升到了块上升到了200200块，其中一块，其中一些死区面积达数千平方英里。罗伯特些死区面积达数千平方英里。罗伯特 达艾斯是弗吉尼达艾斯是弗吉尼亚州的威廉及玛丽学院的生态学家，曾经协助联合国亚州的威廉及玛丽学院的生态学家，曾经协助联合国环境署调查过海洋死区的数目，认为现在全球海岸线环境署调查过海洋死区的数目，认为现在全球海岸线有有400400多块已知死区，海底面积大约有多块已知死区，海底面积大约有9500095000平方英里。平方英里。第3页，本讲稿共14页这无论对于鱼类还是吃鱼的人类来说都不是好消息。由于过度捕捞、珊瑚礁的死亡以及沼泽地、红树林和其他为许多珍稀物种提供繁殖温床的海岸

7、环境的消失，全球的鱼类供应都出现了问题。生物学家还不能确定氧气的耗尽对摇摇欲坠的渔业生产的下滑有多大影响这个问题现在是海洋科学领域一个热门争论的话题但是很少有专家否认死区的增加仅仅是个对渔业的损害问题。第4页，本讲稿共14页Indeed,severe hypoxia：haipksi低氧,as scientists refer to the phenomenon,has been linked to the collapse of fisheries and a lobster fishery.Hypoxic waters have a relatively subtle impact on f

8、ish.Most of the effects of low oxygen on fish stocks are what we call sub-lethal,says Diaz.It doesnt kill the fish but stresses them.It affects their growth,it reduces their reproductive output,and makes them more susceptible易受.影响的to disease.第5页，本讲稿共14页事实上，正如科学家对这一现象所提到的那样，海水严重的低氧状态跟渔业和龙虾渔业的衰退有关。低氧的

9、海水对鱼类有相当微妙的影响。“我们把海水低氧对鱼类资源的大多数影响称作亚致命，”达艾斯说，“低氧不会直接导致鱼类死亡，但是却会给它们造成压力，影响它们的生长，减少繁殖产量，使它们更容易受到疾病的影响。”第6页，本讲稿共14页The best way to prevent this from happening would be to reduce the The best way to prevent this from happening would be to reduce the amount of nitrogen introduced into the ocean.amount of

10、 nitrogen introduced into the ocean.If,for example,If,for example,farmers in the upper part of the U.S.were given a financial farmers in the upper part of the U.S.were given a financial incentive to plant crops like winter wheat,rather than leaving incentive to plant crops like winter wheat,rather t

11、han leaving their fields fallow(their fields fallow(休耕休耕)after the fall harvest,much of the)after the fall harvest,much of the nitrogenous fertilizer that would normally get washed into nitrogenous fertilizer that would normally get washed into waterways by spring thaws could instead be absorbed int

12、o winter waterways by spring thaws could instead be absorbed into winter grain crops.Measures of this sort,if uniformly implemented,could grain crops.Measures of this sort,if uniformly implemented,could all but eliminate the Gulf of Mexicos famously ballooning dead all but eliminate the Gulf of Mexi

13、cos famously ballooning dead zone.Such changes to farm management zone.Such changes to farm management arent likely to be cheap or arent likely to be cheap or easy to implementeasy to implement.But,as Diazs study suggests,the consequences.But,as Diazs study suggests,the consequences of inaction migh

14、t prove infinitely more expensive.of inaction might prove infinitely more expensive.第7页，本讲稿共14页防止海洋死区的最好办法就是减少流入海洋的氮气。比如，如果美国地势较高地区的农民在财政上予以激励，使其种植像冬麦这样的农作物，而不是在秋收后休耕，这样大多数原本会在春天冰雪融化时被冲到河流中的氮肥就会被冬天种植的农作物所吸收。这种措施如果被统一执行，几乎会消除墨西哥湾有名的扩张死区。但是这样的农业管理转变代价不低，也不容易实施。但正如达艾斯的研究所示，如果不采取任何措施，其后果可能会导致付出更加昂贵的代价。第

15、8页，本讲稿共14页patch/pt/n.patch/pt/n.补丁；斑；一小块地补丁；斑；一小块地 vt.vt.补，修补补，修补roughly/rfli/ad.roughly/rfli/ad.粗糙地；毛糙地；概略地粗糙地；毛糙地；概略地mangrove forest n.mangrove forest n.红树林红树林depletion /dipli:n/n.depletion /dipli:n/n.消耗，逐渐耗尽消耗，逐渐耗尽teeter/ti:t/vi.teeter/ti:t/vi.摇摆，摇摇欲坠，犹豫不决，上下往摇摆，摇摇欲坠，犹豫不决，上下往复的运动复的运动n.n.翘翘板翘翘板det

16、riment/detrimnt/n.detriment/detrimnt/n.损害，伤害损害，伤害susceptible /sseptbl/a.susceptible /sseptbl/a.易受影响的；过敏的；能易受影响的；过敏的；能经受的经受的fallow/flu/a.fallow/flu/a.休耕的休耕的第9页，本讲稿共14页1.From the first paragraph,we can learn that _.no living things can be found in dead zones.theres no oxygen in the dead zone waters.th

17、e coverage of dead zones is increasing alarmingly.the phenomenon of dead zone was firstly found by UNEP.第10页，本讲稿共14页2.Whats the impact of dead zones on fishery according to the second paragraph?A)They caused a great trouble in fish supply.B)They led to the great decline of fisheries.C)They reduced t

18、he breeding grounds of fish.D)They would bring more than harm to fisheries.第11页，本讲稿共14页3.From the passage we can learn that the hypoxia in water_.A)makes the fertility(繁殖力)of fish decrease.B)directly leads to the death of fish.C)reduces the output of fish harvest.D)causes the rise of pressure in wat

19、er.第12页，本讲稿共14页4.According to the author,which factor plays the main role in preventing the waters from becoming dead zones?A)The attitude of American farmers.B)The amount of nitrogen into the sea.C)The support of U.S.government.D)The types of crops to be planted.第13页，本讲稿共14页5.The measure raised by the author in the last paragraph _.A)might be supported by the U.S.government.B)is easy to be carried out uniformly in U.S.C)is a costly program but really worthwhile.D)would never be realized for the high cost.第14页，本讲稿共14页