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
56
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.
Oceanographers are concerned because
选项
A、their knowledge of this phenomenon is limited.
B、they believe the oceans are dying.
C、they fear an invasion from outer space.
D、they have identified thousands of alien webs.
答案
A
解析
海洋学家担忧的主要原因是:“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.”
转载请注明原文地址:https://kaotiyun.com/show/tXqO777K
0
专业英语八级
相关试题推荐
Whybankruptyourselfinaso-calledoldpeople’shome?Tryahealthspa—itmightactuallybecheaper.SometimesIseeoldl
TheInternetisanexcellentsourceforfindingmanytypesofinformationandforkeepingupwithnewdevelopmentsintheworld.
NextmonthalargegroupofBritishbusinesspeoplearegoingtoAmericaonaventurewhichmaygenerateexportearningsforthe
游泳是(体育)锻炼的最好方式之一。它能改善心脏功能。它也能帮助血液循环。游泳会促进肌肉发达。它甚至会增强肺部功能。(身体有)残疾的人如不能参与其他运动,可以通过游泳保持身体健康。对于父母来说,确保他们的孩子在年幼时就学游泳,是个不错的选择。这是一项孩子们可
ThemostwidelydiscussedalternativetothetraditionalcampusistheInternetUniversity—avoluntarycommunitytoscholars/tea
Theterm"Americandream"wasfirstusedin【B1】______inanovelwrittenbyHoratioAlger:RaggedDick.Themessagewas:Nomatte
WhenmypredecessorsatTimereviewedecologistRachelCarson’sbookSilentSpring50yearsagothismonth,theywerelessthan
InlikemannerwecannotreferthewholephenomenaoftheRenaissancetoanyonecauseorcircumstance,orlimitthemwithinthe
A、Hedeniesthecurrentstalemateandthebrewingconfrontation.B、TheUnitedStatesthreatstoimposenewsanctionsagainstIra
TheDeclarationofIndependencewaswrittenby______.
随机试题
男性,67岁,诊断肺心病3年,咳、痰、喘伴双下肢水肿加重1周,查体:双肺可闻及大量湿性啰音,心率107次/min,肝于肋缘下2横指,有触痛。白细胞及分类均高,血气分析:pH7.33,PaO245mmHg,PCO275mmHg,HCO3-35mm
A.卫生法基本原则B.法的规范作用C.卫生法的立法目的D.法的社会作用E.卫生工作社会化法作为一种特殊社会规范,其自身所具有的、对人们的行为发生影响的性能称为
下列药品中,没有纳入《抗菌药物临床应用管理办法》适用范围的是()。
某人工挖孔嵌岩灌注桩桩长为8m,其低应变反射波动力测试曲线如图10一4所示。问该桩桩身完整性类别及桩身波速值符合下列哪个选项的组合?()[2008年真题]
北京巨象工程公司为提高竞争优势,从日本订购进口成套装卸设备。该设备投入使用后,接连发生非正常技术性故障,经合法检验机构检验,确认为该设备中部分关键件品质不良。境内外交易双方协商决定,对该套改作削价30%的处理,并由境外供货商免费补偿进口部分关键件。
(2018年)某增值税一般纳税企业销售商品,商品已发出但不符合销售收入确认条件,增值税专用发票已开出,该企业确认应交增值税时贷记的会计科目是()。
【2018上】简述班主任应具备的基本条件。
两个相互矛盾的命题不能同假,必有一真。这是()的内容。
下面关于关系的叙述,错误的是( )。
Wherecouldmyson______thekey?Icouldn’tfindanywhere.
最新回复
(
0
)