首页
登录
职称英语
Every silver lining has its cloud. At the moment, the world’s oceans absorb
Every silver lining has its cloud. At the moment, the world’s oceans absorb
游客
2023-12-03
69
管理
问题
Every silver lining has its cloud. At the moment, the world’s oceans absorb a million tonnes of carbon dioxide an hour. Admittedly that is only a third of the rate at which humanity dumps the stuff into the atmosphere by burning fossil fuels, but it certainly helps to slow down global wanning. However, what is a blessing for the atmosphere turns out to be a curse for the oceans. When carbon dioxide dissolves in water it forms carbonic acid. At the moment, sea water is naturally alkaline — but it is becoming less so all the time.
The biological significance of this acidification was a topic of debate among scientists. Many species of invertebrate have shells or skeletons made of calcium carbonate. It is these, fossilized, that form rocks such as chalk and limestone. And, as anyone who has studied chemistry at school knows, if you drop chalk into acid it fizzes away to nothing. Many marine biologists therefore worry that some species will soon be unable to make their protective homes. Many of the species most at risk are corals.
The end of the Permian period, 252m years ago, was marked by the biggest extinction of life known to have happened on Earth. At least part of the cause of this extinction seems to have been huge volcanic eruptions that poured carbon dioxide into the atmosphere. But some groups of animals became more extinct than others. Sponges, corals and brachiopods were particularly badly hit.
Rather than counting individual species of fossils, which vary over time, paleontologists who study extinction usually count entire groups of related species, called genera. More than 90% of Permian genera of sponges, corals and brachiopods vanished in the extinction. By contrast, only half of the genera of mollusks and arthropods disappeared.
This is because mollusks and arthropods are able to buffer the chemistry of the internal fluids from which they create their shells. This keeps the acidity of those fluids constant.
Sponges, corals and brachiopods, however, cannot do this.
The situation at the moment is not as bad as it was at the end of the Permian. Nevertheless, calculations suggest that if today’s trends continue, the alkalinity of the ocean will have fallen by half a pH unit by 2100. That would make some places, such as the Southern Ocean, uninhabitable for corals. Since corals provide habitat and food sources for many other denizens of the deep, this could have a profound effect on the marine food web.
No corals, no sea urchins and no who-knows-what-else would be bad news indeed for the sea. Those who blithely factor oceanic uptake into the equations of what people can get away with when it comes to greenhouse-gas pollution should, perhaps, have second thoughts. [br] The best title for the passage is______.
选项
A、Global Warming
B、Sour Times
C、Carbon Dioxide
D、Ocean Acidity
答案
B
解析
综合题。虽然四个选项在文中都有所涉及,但B为最佳标题,原因有二:一是海水酸性增强,与sour的本义对应;二是海洋生物面临更加恶化的环境,生存将受到考验,与sour的引申义对应,恰好一语双关。
转载请注明原文地址:https://tihaiku.com/zcyy/3240802.html
相关试题推荐
Everysilverlininghasitscloud.Atthemoment,theworld’soceansabsorb
Everysilverlininghasitscloud.Atthemoment,theworld’soceansabsorb
Everysilverlininghasitscloud.Atthemoment,theworld’soceansabsorb
Itisinterestingtoreflectforamomentuponthedifferencesintheareas
Itisinterestingtoreflectforamomentuponthedifferencesintheareas
Itisinterestingtoreflectforamomentuponthedifferencesintheareas
Itisinterestingtoreflectforamomentuponthedifferencesintheareas
Itisinterestingtoreflectforamomentuponthedifferencesintheareas
Itisinterestingtoreflectforamomentuponthedifferencesintheareas
Weuselanguageeveryday.Weliveinaworldofwords.Hardlyanymomentpa
随机试题
Whydoesthewomanneedthejob?[br][originaltext]M:So,you’veappliedfort
Fromthehealthpointofviewwearelivinginamarvelousage.Weareimmuni
TheUnitedStatescourtsystem,aspartofthefederalsystemofgovernment,
下表为某公司四个部门2009年全年的营销总费用,以及营销总费用占总销售额的比例。
城市道路横断面规划设计的主要任务是在满足管线敷设以及()等要求的前提下,经
特征性效标考量员工是怎样一个人。其侧重点是( )。A.员工如何工作 B.个人
根据《招标投标法》的相关规定,()可以作为履约保证金。A、现金支票B、银行汇票
对于质押担保贷款,出质人应向商业银行提交的材料有()。A.担保意向书 B.出
三型卡环的特点是A.固位好,稳定和支持作用稍差 B.固位和稳定好,支持作用稍差
某知名啤酒生产企业,为满足市场需求,不断开发啤酒新品种,开发适合不同顾客群体的啤
最新回复
(
0
)