首页
登录
职称英语
The amount of floating plastic trapped in a north Atlantic current system ha
The amount of floating plastic trapped in a north Atlantic current system ha
游客
2023-08-15
62
管理
问题
The amount of floating plastic trapped in a north Atlantic current system hasn’t got any bigger in 22 years, despite more and more plastic being thrown away. Since 1986 students taking samples of plankton (浮游生物) in the Atlantic and Caribbean Oceans have also noted when their nets caught plastic litter. Kara Lavender and colleagues at the Sea Education Association in Woods Hole, Massachusetts, analysed the data, and found that of 6136 samples recorded, more than 60 per cent included pieces of plastic, typically just millimetres across. The areas of highest plastic concentration are within the north Atlantic sub-tropical gyre (环流), where currents gather the litter.
Lavender and her team were surprised to find that the amount of floating plastic had not increased in the gyre. Although it has been illegal since the 1970s for ships to throw plastic overboard, Lavender thinks that the overall rate of plastic rubbish reaching the ocean will have increased, given the fivefold increase in global production of plastic since 1976. "Where the extra plastic is going is the big mystery," she says. Plastic resists bio-degradation and can last decades or more in the ocean. Eventually sunlight and wave motion break it into smaller pieces, which can be harmful to marine life—blocking the stomachs of fish and seabirds, for example.
Some experts suggest that the plastic might be degrading into pieces small enough to pass through the 0.3-millimetre-mesh nets used in the study, or becoming coated in biofilms and sinking out of range of the nets. However it is unclear why the rate of degradation during the study period should have increased to offset the extra plastic going into the ocean. Lavender says it is unlikely that ocean currents are pushing plastic out of the gyre, although Simon Boxall of the National Oceanography Centre in Southampton, UK, who wasn’t involved in the study, disagrees. He says the Atlantic gyre has an exit strategy in the form of the Gulf Stream. "We’ve seen high levels of plastic in the Arctic." he says.
Wherever it is going at the moment, the plastic on our oceans will eventually be broken down into microscopic pieces and individual molecules whose environmental effect is unknown. "The million-dollar question is, is it causing any damage?" says Boxall.
"When plastic particles get so small are they just like fibre going through the system? Some studies suggest that persistent chemicals in newer plastics function as endocrine (内分泌) disruptors and simulated hormones." And this fine-grained plastic is very long-lived. "The depressing thing is it’s likely to remain in the oceans essentially forever," says Lavender. [br] According to Lavender, newer plastics can be broken down into microscopic particles that ______.
选项
A、benefit the marine life
B、are threats to the ocean
C、stay in the ocean for long
D、are harmless to the system
答案
C
解析
解题关键要弄清microscopic particles有什么特点。最后一段倒数第2句中的fine—grained plastic“细小的塑料”指的就是题干中的microscopic particles,可知这些颗粒存在的时间会非常长久。而文章最后一句又提到,这些颗粒有可能永远留在大海里。最后可知,本题应选C。
转载请注明原文地址:https://tihaiku.com/zcyy/2927403.html
相关试题推荐
IfoursolarsystemhasaHell,it’sVenus.Theairischokedwithfouland
IfoursolarsystemhasaHell,it’sVenus.Theairischokedwithfouland
IfoursolarsystemhasaHell,it’sVenus.Theairischokedwithfouland
Memoryappearstobestoredinseveralpartsofthelimbic(边缘的)systemofthe
TheAmerican【C1】______system,isorganizedaroundabasicallyprivate-enterp
TheAmerican【C1】______system,isorganizedaroundabasicallyprivate-enterp
TheAmerican【C1】______system,isorganizedaroundabasicallyprivate-enterp
TheAmerican【C1】______system,isorganizedaroundabasicallyprivate-enterp
TheAmerican【C1】______system,isorganizedaroundabasicallyprivate-enterp
TheAmerican【C1】______system,isorganizedaroundabasicallyprivate-enterp
随机试题
B&ZFromtheDeskofMileMo
GeneticallyModifiedFoods—FeedtheWorld?[A]Ifyouwanttosp
Inordertobesuccessfulasanengineer,shehadtobecome______atmathematic
共用题干 IKnowJustHowYouFeelDoyoufee
黄酮与黄酮醇类化合物结构上的区别是A.2,3位有无双键B.3位有无氧取代基C.B
实施调整给药方案过程中,使“血药浓度波动幅度较小”的调整方式是A:延长给药间隔
主要诱发肾盂肾炎的疾病是A.心力衰竭 B.肺炎球菌性肺炎 C.慢性消耗性疾病
老邢今年73岁,退休之后一直哀叹自己虚度一生,毫无成就,想重新开始又力不从心,根
甲涉嫌故意杀人被提起公诉,可能判处死刑。关于本案诉讼程序,下列哪一选项是正确的?
(2012年真题)下列合同条款中,属于劳动合同必备条款的是()A.试用期 B
最新回复
(
0
)