Section outline

  • General

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  • 化学合成

    What will you learn
    ::你会学到什么

    • The process of chemosynthesis
      ::化合过程
    • How different organisms perform chemosynthesis
      ::不同生物如何进行化学合成

    A Pompeii worm showing its unique, bacteria-covered back, adapted to extreme temperatures.

    Is it possible to live in temperatures over 175°F?
    ::能否在175°F以上的温度下生活?

    It is if you're a Pompeii worm. The Pompeii worm, the most heat-tolerant on Earth, lives in the deep ocean at super-heated hydrothermal vents. Covering this deep-sea worm's back is a fleece of . These microbes contain all the genes necessary for life in extreme environments.
    ::如果你是庞贝虫。 地球上最耐热的庞贝虫, 生活在深海超热热热液喷口。 覆盖这个深海虫的背部就是一团毛虫。 这些微生物包含了在极端环境中生活所需的所有基因。

    Chemosynthesis
    ::化学合成

    Why do bacteria that live deep below the ocean’s surface rely on chemical compounds instead of sunlight for energy to make food ?
    ::为什么生活在海洋表面深处的细菌依赖化学化合物而不是阳光来生产食物?

    Most autotrophs make food by , but this isn’t the only way that autotrophs produce food. Some bacteria make food by another process, which uses chemical energy instead of light energy. This process is called chemosynthesis . In chemosynthesis, one or more carbon molecules (usually carbon dioxide or methane, CH 4 ) and nutrients is converted into organic matter, using the oxidation of inorganic molecules (such as hydrogen gas, hydrogen sulfide (H 2 S) or ammonia (NH 3 )) or methane as a source of energy, rather than sunlight. In hydrogen sulfide chemosynthesis, in the presence of carbon dioxide and oxygen, (CH 2 O) can be produced:
    ::大部分的自养养分都是通过自养成食物,但这不是产生食物的唯一方法。有些细菌通过另一种过程生产食物,这种过程使用化学能源而不是光能。这个过程被称为化学合成。在化学合成中,一种或多种碳分子(通常是二氧化碳或甲烷、CH4)和养分被转化成有机物质,使用无机分子(如氢气、硫化氢(H2S)或氨(NH3)的氧化或甲烷作为能源来源,而不是阳光。 在硫化氢化学合成中,在二氧化碳和氧存在的情况下,(CH2O)可以产生:

    CO 2 + O 2 + 4H 2 S → CH 2 O + 4S + 3H 2 O
    ::CO2 + O2 + O2 + 4H2S + CH2O + 4S + 3H2O

    Many organisms that use chemosynthesis are extremophiles , living in harsh conditions, such as in the absence of sunlight and a wide range of temperatures, some approaching the boiling point. Some chemosynthetic bacteria live around deep-ocean vents known as “black smokers.” Compounds such as hydrogen sulfide, which flow out of the vents from Earth’s interior, are used by the bacteria for energy to make food. Consumers that depend on these bacteria to produce food for them include giant tubeworms, like those pictured in Figure . These organisms are known as chemoautotrophs . Many chemosynthetic microorganisms are consumed by other organisms in the ocean, and symbiotic associations between these organisms and respiring heterotrophs are quite common.
    ::使用化学合成物的许多生物都是极端嗜血动物,生活在严酷的条件下,如没有阳光和广泛的温度,有些接近沸点。有些化学合成细菌生活在被称为“黑烟者”的深海喷口周围。 硫化氢等化合物从地球内部的喷口流出,被细菌用来制造食物。 依赖这些细菌生产食物的消费者包括巨型管虫,如图中所描绘的。 这些生物被称为化生养殖。 许多化学合成微生物被海洋中的其他生物吸收,这些生物与再生异性营养素之间的共生联系非常常见。

    A dense cluster of giant tubeworms found near deep-ocean hydrothermal vents.
    Tubeworms deep in the Galapagos Rift get their energy from chemosynthetic bacteria. Tubeworms have no mouth, eyes or stomach. Their survival depends on a symbiotic relationship with the billions of bacteria that live inside them. These bacteria convert the chemicals that shoot out of the hydrothermal vents into food for the worm.
    DID YOU KNOW?
    The chemosynthetic bacteria present in some deep lakes produce methane. This results in the formation of large bubbles of highly flammable methane gas under the frozen lakes during winter. Lakes such as these and natural wetlands contribute to the production of a significant amount of methane, a greenhouse gas .
     

    Summary
    ::摘要

    • Chemosynthesis is a process in which some organisms use chemical energy instead of light energy to produce "food."
      ::化学合成是一种过程,一些生物利用化学能源而不是光能生产“食物”。

    Review
    ::回顾

    1. What is chemosynthesis?
      ::什么是化学合成?
    2. Why do bacteria that live deep below the ocean’s surface rely on chemical compounds instead of sunlight for energy to make food?
      ::为什么生活在海洋表面深处的细菌依赖化学化合物而不是阳光来生产食物?
    3. Describe the habitats of extremophiles?
      ::描述极端嗜血动物的栖息地?