12.22 碳循环
Section outline
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Why is Earth getting warmer?
::为什么地球变暖了?What happens if carbon is not removed from the atmosphere ? The excess carbon dioxide in the atmosphere is contributing to a global rise in Earth’s temperature, known as global warming . Where does this carbon dioxide come from? Burning gas to power our cars and burning coal to generate electricity are two main sources of the excess carbon dioxide.
::如果碳不从大气中清除出来呢? 大气中的超量二氧化碳正在导致全球气温上升,即全球升温。 二氧化碳来自何处? 燃烧燃气为汽车提供动力和燃烧煤炭发电是二氧化碳过剩的两个主要来源。The Carbon Cycle
::碳循环Carbon is one of the most common elements found in living organisms . Chains of carbon molecules form the backbones of many organic molecules, such as carbohydrates , proteins , and lipids . Carbon is constantly cycling between living organisms and the atmosphere ( Figure ). The cycling of carbon occurs through the carbon cycle .
::碳是活生物体中最常见的元素之一。碳分子链是碳水化合物、蛋白质和脂类等许多有机分子的脊柱。碳不断在活生物体和大气之间循环(图 )。碳的循环通过碳循环发生。Living organisms cannot make their own carbon, so how is carbon incorporated into living organisms? In the atmosphere, carbon is in the form of carbon dioxide gas (CO 2 ). Recall that plants and other capture the carbon dioxide and convert it to glucose (C 6 H 12 O 6 ) through the process of . Then as animals eat plants or other animals, they gain the carbon from those organisms.
::活生物体不能制造自己的碳,所以碳是如何融入活生物体的?在大气中,碳的形式是二氧化碳气(CO2 ) 。 回顾植物和其他生物通过过程捕捉二氧化碳并将其转化为葡萄糖(C6H12O6 ) 。 然后,当动物食用植物或其他动物时,它们从这些生物体中获取碳。The chemical equation of photosynthesis is 6CO 2 + 6H 2 O → C 6 H 12 O 6 + 6O 2 .
::光合作用化学方程式为 6CO2 + 6H2O C6H12O6+ 6O2。How does this carbon in living things end up back in the atmosphere? Remember that we breathe out carbon dioxide. This carbon dioxide is generated through the process of , which has the reverse chemical reaction as photosynthesis. That means when our cells burn food (glucose) for energy , carbon dioxide is released. We, like all animals, exhale this carbon dioxide and return it back to the atmosphere. Also, carbon is released to the atmosphere as an organism dies and decomposes.
::活物中的碳是如何回到大气层的? 记住, 我们吸入二氧化碳。 这种二氧化碳是通过 光合作用产生反化学反应的过程产生的。 这意味着当我们的细胞燃烧食物(葡萄糖)作为能源时, 二氧化碳就会释放。 我们和所有动物一样, 向大气中排放二氧化碳。 同时, 当有机体死亡和分解时, 碳会释放到大气中。can be described as a cycle, as one uses carbon dioxide (and water) and makes oxygen (and glucose), and the other uses oxygen (and glucose) and makes carbon dioxide (and water).
::可以被描述为一个循环,因为一个人使用二氧化碳(和水),制造氧气(和葡萄糖),而另一个人使用氧气(和葡萄糖),制造二氧化碳(和水)。The carbon cycle. The cycling of carbon dioxide in photosynthesis and cellular respiration are main components of the carbon cycle. Carbon is also returned to the atmosphere by the burning of organic matter (combustion) and fossil fuels and decomposition of organic matter.
::碳循环:光合作用和细胞呼吸中的二氧化碳循环是碳循环的主要组成部分,碳也通过燃烧有机物(燃烧)和化石燃料以及有机物分解而返回大气层。Formation of Fossil Fuels
::化石燃料的形成Millions of years ago, there were so many dead plants and animals that they could not completely decompose before they were buried. They were covered over by soil or sand, tar or ice. These dead plants and animals are organic matter made out of cells full of carbon-containing (carbohydrates, lipids, proteins and nucleic acids). What happened to all this carbon? When organic matter is under pressure for millions of years, it forms fossil fuels . Fossil fuels are coal, oil, and natural gas.
::数百万年前,有如此多的死植物和动物在被埋之前无法完全分解,它们被土壤或沙子、焦油或冰覆盖。这些死植物和动物都是由含碳细胞(碳水化合物、脂类、蛋白质和核酸)组成的有机物质。这些碳发生了什么?当有机物质受到数百万年的压力时,它们形成化石燃料。化石燃料是煤、油和天然气。When humans dig up and use fossil fuels, we have an impact on the carbon cycle ( Figure ). This carbon is not recycled until it is used by humans. The burning of fossil fuels releases more carbon dioxide into the atmosphere than is used by photosynthesis. So, there is more carbon dioxide entering the atmosphere than is coming out of it. Carbon dioxide is known as a greenhouse gas , since it lets in light energy but does not let heat escape, much like the panes of a greenhouse. The increase of greenhouse gasses in the atmosphere is contributing to a global rise in Earth’s temperature, known as global warming or global climate change .
::当人类挖掘和使用化石燃料时,我们就会对碳循环产生影响(图 ) 。 这种碳在被人类使用之前是不会被回收的。 化石燃料的燃烧在大气中释放的二氧化碳比光合作用还多。 因此,进入大气层的二氧化碳比从大气中排放的二氧化碳还多。 二氧化碳被称为温室气体,因为它让光能进入,但不能让热泄漏,就像温室的玻璃一样。 大气中温室气体的增加正在推动全球气温的上升,即全球升温或全球气候变化。Human activities like burning gasoline in cars are contributing to a global change in our climate.
::汽车中燃烧汽油等人类活动正在促成全球气候的变化。Summary
::摘要-
During the carbon cycle, animals and plants add carbon dioxide to the atmosphere through cellular respiration, and plants remove carbon dioxide through photosynthesis.
::在碳循环期间,动物和植物通过细胞呼吸在大气中增加二氧化碳,植物通过光合作用清除二氧化碳。 -
The burning of fossil fuels releases more carbon dioxide into the atmosphere, contributing to global warming.
::燃烧化石燃料将更多的二氧化碳释放到大气中,导致全球变暖。
Explore More
::探索更多Use the resource below to answer the questions that follow.
::利用以下资源回答以下问题。-
Organic Carbon and the World Around Us
from USGS
(7:11)
::来自USGS的有机碳和我们周围的世界(7:11)
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What are two types of carbon? What type is carbon dioxide (CO
2
)? What is an example of the other type?
::什么是两种碳?哪些是二氧化碳(CO2)?另一种碳(CO2)的一个例子是什么? -
How can carbon aid the spread of toxic substances?
::碳如何能帮助有毒物质的扩散? -
Why are the reactivity and binding capabilities of carbon crucial to life?
::为什么碳的回动性和约束性能力对生命至关重要?
Review
::回顾-
What biological process releases carbon back into the atmosphere?
::哪些生物过程将碳释放回大气层? -
What human activities have thrown the carbon cycle off balance?
::哪些人类活动使碳循环失去平衡? -
Why is carbon dioxide a greenhouse gas?
::为什么二氧化碳是温室气体? -
What is the outcome of the increase of greenhouse gasses?
::温室气体增加的结果是什么?
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During the carbon cycle, animals and plants add carbon dioxide to the atmosphere through cellular respiration, and plants remove carbon dioxide through photosynthesis.
