首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Every minute of every day, what ecologist James Carlton calls a global "conveyor belt" redistributes ocean organisms. It’s plane
Every minute of every day, what ecologist James Carlton calls a global "conveyor belt" redistributes ocean organisms. It’s plane
admin
2010-03-25
34
问题
Every minute of every day, what ecologist James Carlton calls a global "conveyor belt" redistributes ocean organisms. It’s planetwide biological disruption that scientists have barely begun to understand.
Dr Carlton -- an oceanographer at Williams College in Williamstown, Mass. -- explains that, at any given moment, "there are several thousand (marine) species (traveling)... in the ballast water of ships." These creatures move from coastal waters where they fit into the local web of life to places where some of them could tear that web apart. This is the larger dimension of the infamous invasion of fish-destroying, pipe- clogging zebra mussels.
Such voracious invaders at least make their presence known. What concerns Carlton and his fellow marine ecologists is the lack of knowledge about the hundreds of alien invaders that quietly enter coastal waters around the world every day. Many of them probably just die out. Some benignly -- or even beneficially -- join the local scene. But some will make trouble.
In one sense, this is an old story. Organisms have ridden ships for centuries. They have clung to hulls and come along with cargo. What’s new is the scale and speed of the migrations made possible by the massive volume of ship-ballast water -- taken in to provide ship stability -- continuously moving around the world...
Ships load up with ballast water and its inhabitants in coastal waters of one port and dump the ballast in another port that may be thousands of kilometers away. A single load can run to hundreds of gallons. Some larger ships take on as much as 40 million gallons. The creatures that come along tend to be in their larva freefloating stage. When discharged in alien waters they can mature into crabs, jellyfish, slugs, and many other forms.
Since the problem involves coastal species, simply banning ballast dumps in coastal waters would, in theory, solve it. Coastal organisms in ballast water that is flushed into midocean would not survive. Such a ban has worked for North American Inland Waterway. But it would be hard to enforce it worldwide. Heating ballast water or straining it should also halt the species spread. But before any such worldwide regulations were imposed, scientists would need a clearer view of what is going on.
The continuous shuffling of marine organisms has changed the biology of the sea on a global scale. It can have devastating effects as in the case of the American comb jellyfish that recently invaded the Black Sea. It has destroyed that sea’s anchovy fishery by eating anchovy eggs. It may soon spread to western and northern European waters.
The maritime nations that created the biological "conveyor belt" should support a coordinated international effort to find out what is going on and what should be done about it.
The identified cause of the problem is
选项
A、the rapidity with which larvae mature.
B、a common practice of the shipping industry..
C、a century-old species.
D、the worldwide movement of ocean currents.
答案
B
解析
造成问题的主要原因,根据文章中间几段的描述,是因为一直以来船舶需要装载压舱水。从一个地方装载,再在另一个地方倒掉,这已是船舶航运业的惯例了。
转载请注明原文地址:https://kaotiyun.com/show/CXqO777K
0
专业英语八级
相关试题推荐
A、Nomorethan1800years.B、About2000years.C、Nearly4000years.D、Over5000years.C
A、Refinedoil.B、Mineralores.C、Coalgas.D、Naturalgas.D
A、Theyoftengoboatingonthelake.B、Thereisaverygoodmarketneartheplace.C、NotmanyEnglishpeoplegothere.D、Therea
Afteradecades-longsearchforamanageablebalancebetweenmotherhoodandcareer,agroupofAmericanwomenhavefoundworkin
Next,let’stalkaboutearthquakesonourPlanet.Somecountrieshavelargenumbersofearthquakes.Japanisoneofthem.Others
Next,let’stalkaboutearthquakesonourPlanet.Somecountrieshavelargenumbersofearthquakes.Japanisoneofthem.Others
A、Workinginatravelagency.B、OrganizingaBBQparty.C、TeachingEnglishtoChinesestudents.D、LearningChinese.D
WhenmypredecessorsatTimereviewedecologistRachelCarson’sbookSilentSpring50yearsagothismonth,theywerelessthan
InlikemannerwecannotreferthewholephenomenaoftheRenaissancetoanyonecauseorcircumstance,orlimitthemwithinthe
A、Consciousdestruction.B、Tourismindustry.C、Theft.D、Carelessness.D
随机试题
3个月女孩,生后有窒息,吃奶少,睡眠时间少,安静,少哭,少动,大便3~4天一次,干燥,皮肤温度低,心率100次/分,心音低钝,腹膨隆,有脐疝。本病可能的发病原因有
下列关于计算机程序的叙述,正确的是
(英语类学生必做)ThethreemaintypesofsecondaryeducationintheUnitedStateshavebeenprovidedbytheLatingrammarschool,t
严重的心脏瓣膜病可引起晕厥,最常见的是
某矿场的采石工,年龄27岁,工龄1年半。因主诉咳嗽、胸痛、气短等症状就诊。患者自述,采矿场工作条件很差,无防尘措施。X线胸片呈肺纹理增加,伴有块状阴影和典型结节。诊断时应注意哪种尘肺
抽象危险犯
出口口岸()净重()
下列关于账簿设置的表述,不正确的是()。
“正始之音”的文学作品特征是()。
阿拉伯人被誉为“东西方文明交流的使者”,对世界文化的传播与交流做出过重大贡献。下列史实不能说明这一观点的是:
最新回复
(
0
)