生化翻译
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new bacterial group that contain bacteriochlorophyll, yet grow aerobically, has forced a revision of
this view (Box 2.2).含有细菌叶绿素的需氧生长的新的细菌群体，已经迫使这篇文章进行了修改。
Although they grow aerobically, these types do not produce O2 from
photosynthesis. 虽然它们是需氧生长的，但是这些类型不能通过光合作用产生O2。
As noted in Section 5.2.2, the Roseobacter clade is well-represented in culture independent
surveys. Like the purple bacteria, the aerobic anoxygenic (AAnP) photobacteria contain
a range of carotenoid pigments.正如在章节5.2.2所记下的那样，在独立培养调查中玫瑰杆菌分化枝是很好的代表。像紫色细菌，需氧的不产生氧气的光细菌包含一系列的类胡萝卜素色素。
However, the photosynthetic apparatus is not as well structured and
the complex membrane invaginations typical of the anaerobic phototrophs are not seen in the aerobic
types.无论如何，光合作用的细胞器并不是被很好的构造并且复杂的细胞膜内陷是厌氧的光养生物的典型特征，这一特征没有在需氧的类型中被发现。
This probably explains why the AAnP bacteria cannot use light as a sole source of energy and
rely on various organic compounds as a source of carbon and energy.
这很可能解释了为什么需氧的不产氧细菌不能利用光作为唯一的能量来源并且依赖各种各样的有机化合物作为碳源和能源。
It is now known that the Roseobacter clade contains both culturable and nonculturable types, as well
as phototrophic and nonphototrophic representatives.
玫瑰杆菌分化枝包含可培养的和不可培养的类型与光营养的和非光营养的代表一样现在已经被知道，
These are widely distributed in coastal and
oceanic plankton and occur in a wide range of associations with other marine organisms.
这广泛的分布在沿海以及海洋的浮游生物中并且发生在许多各种不同的的与其他海洋生物结合的结合体中。
In molecular studies, the Roseobacter clade emerges as the second most abundant 16S rRNA gene
clone type (over 30% of clones).在分子的研究中，玫瑰杆菌分化枝作为第二最丰富的16S rRNA基因复制类型呈现（超过复制体的百分之三十）
Their association with blooms of algae and dinoflagellates have
been particularly studied, and they may play a role in the formation of dinoflagellate toxins (Box
12.2). 它们与藻类以及鞭毛藻类水华的结合体已经特别地被研究，并且它们可能在腰鞭毛虫毒素的形成中扮演重要角色(Box12.2）
Despite their obvious ubiquitous presence in ocean water, it is currently difficult to be sure of
the role of this group in ecological processes.
由于它们在海水中明显的普遍存在，当前很困难去确定它在生态进程的这一类群所扮演的角色。
The diverse metabolic properties
of the group
undoubtedly play a large part in nutrient cycling. For example, Roseobacter has a major role in the
breakdown of DMSP leading to the formation of dimethyl sulfide (DMS), which has great significance
in the global climate (Box 8.1).
这一类群的不同的新陈代谢的特性确实在营养物循环扮演了重要角色。例如，玫瑰杆菌在分解DMSP导致对全球气候具有重要意义的二甲基硫醚的形成中扮演了主要角色。
5.3.3 Green sulfur bacteria绿色硫细菌
The group known as green sulfur bacteria forms a separate lineage distinct from the Proteobacteria,
but resembles the purple sulfur bacteria in metabolism.
这一类群以绿色硫细菌形成单独的与变形菌门不同的世系而著名，但是在新陈代谢上类似紫色硫细菌。
However, sulfur is produced outside of the
cell rather than as intracellular granules.
无论如何，硫被产到了细胞的外部而不是作为细胞内颗粒。
Also, in addition to bacterio-chlorophyll a, green sulfur
bacteria contain bacteriochlorophyll c, d or e. These pigments are contained in a membrane-bound
structure known as the chlorosome.
另外，除了细菌叶绿素a外，绿色硫细菌包含细菌叶绿素c，d或者e。这些色素被包含在被称为是叶绿体的细胞膜限制结构中。
Members of the family Chromatiaceae are common on intertidal
mudflats and as members of consortia in microbial mats and sediments.
着色菌科的家庭成员在潮间带的泥滩是相同的并且作为合作成员存在于在微生物的沉淀物中。
5.4 Oxygenic phototrophs—the Cyanobacteria含氧的光养生物----蓝藻细菌
5.4.1 Nature of the Cyanobacteria蓝细菌的性质（种类）化石证明
The Cyanobacteria is a large and diverse group, and members are characterized by their ability to
carry out photosynthesis in which O2 is evolved, although some anoxygenic Cyanobacteria have
recently been described.
蓝细菌是大的并且是多种多样的类群，并且成员具有执行逐步形成O2的光合作用的能力，尽管一些不产生氧的蓝藻细菌最近已经被发现（描述）。
Cyanobacteria contain chlorophyll a, together with accessory photosynthetic
pigments called phycobilins.
蓝藻细菌包含叶绿素a，和附属的被称作藻胆色素的光合作用色素一起。
This group was formerly known as the ‘blue-green algae’ (due to the
presence of the blue pigment phycocyanin together with the green chlorophyll) and is still treated as
a division of the algae by many marine biologists and phycologists, although Cyanobacteria are
clearly prokaryotes and form one of the major divisions of the domain Bacteria.
这一类群以前被认为是“蓝绿藻”（由于蓝色素藻青蛋白连同绿色的叶绿素的存在）并且仍通过许多海洋生物学家和心理学家被当做藻类的分类来对待，虽然蓝藻细菌
是明显的原核生物并且形成领域细菌
主要分类之一。
Furthermore, many marine genera contain phycoerythrins, which give the cells a red-orange, rather than blue-green,
color.此外，许多海生属包含给予细胞红橙色而不是蓝绿色颜色的藻红蛋白
Fossil evidence, in the form of morphological structures and distinctive biomarkers typical of
the group (hopanoids), suggests that organisms resembling Cyanobacteria may have evolved about 3
billion years ago and the evolution of O2 from the photosynthetic activities of Cyanobacteria (or their
ancestors) was probably responsible for changes in the Earth’s early atmosphere.
化石证明，以形态学结构和有特色的生物指标的形式是这一类群的典型特征（hopanoids），暗示生物体类似蓝藻细菌可能在大约30亿年以前已经逐步形成
并且氧气的演变来自蓝藻细菌光合作用的活动（或者是它们的祖先）大概是地球最早大气变化的原因。
Cyanobacteria occupy very diverse habitats in terrestrial and aquatic environments, including extreme temperatures
and hypersaline conditions.
蓝藻细菌在陆地和水生环境占据许多多种多样的栖息地，包括极端温度和超盐性的条件。
In the marine environment, habitats include the plankton, sea ice and
shallow sediments, as well as microbial mats on the surface of inanimate objects, algae or animal
tissue.
在海洋环境，栖息地包括浮游生物，海上浮冰和浅滩沉淀物，和静物，藻类或动物组织外表上的微生物的垫子（mats）。
Some marine isolates require NaCl plus other marine salts for growth in culture, whilst others
tolerate a range of salt concentrations.
一些海生的隔离群需要氯化钠加上其他的海生的盐分用来培养生长，同时其他的忍受一系列盐浓度。
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5.4.2 Morphology and taxonomy形态学和分类学
The Cyanobacteria are morphologically very diverse, ranging from small undifferentiated rods to
large branching filaments showing cellular differentiation.
蓝藻细菌在形态学上是多种多样的，由一致的大的分支细丝展示细胞区别的棒条体 排列而成。
Unicellular Cyanobacteria divide by binary
fission, whilst some filamentous forms multiply by fragmentation or release of chains of cells.
单细胞的蓝藻细菌通过二次分裂生长分开，同时一些细丝状的形成通过分裂或细胞链的释放而增长。
Many types are surrounded by mucilaginous sheaths that bind cells together.
许多类型被将细胞结合的粘的鞘所包围。
The chlorophyll a is contained within lamellae called phycobilosomes which are often complex and multilayered.
叶绿素a被称作phycobilosomes的时常是复杂的并且多层的壳层所包含。
Cyanobacteria show remarkable ability to adapt the arrangement of their photosynthetic membranes and the proportion
of phycobilin proteins to maximize their ability to utilize light of different wavelengths.
蓝藻细菌显示出非凡的适应它们光合作用的细胞膜排列的能力以及藻胆色素蛋白比例来扩大它们利用不同波段光的能力。
Many Cyanobacteria form intracellular gas vesicles (Section 3.3), which enable cells to maintain themselves
in the photic zone.
许多蓝藻细菌形成细胞内的气泡，
Gas vesicles, as well as mucilaginous sheaths and pigments, also protect cells
from extreme effects of solar radiation (Section 4.6.5).
气泡，和粘液质鞘以及色素一样，也保护细胞免受太阳辐射的极端效果。
Gliding motility is very important in Cyanobacteria that colonize surfaces. Gliding movement, up to 10
μm per second, occurs parallel to the cell’s long axis and involves the production of mucilaginous
polysaccharide slime. There are two possible mechanisms by which gliding occurs.
滑行运动对蓝藻细菌拓展表面来说是非常重要的。滑行运动，相当于10um每秒，出现平行于细胞的长轴并且牵涉粘液质的多糖粘液的产生。
通过滑行的出现这是两种可能的机制。
One is the propagation of waves moving from one end of the filament to the other, created by the contraction
of protein fibrils in the cell wall.
其中之一是波浪传播使丝状体从一个末端传到另一个末端，由细胞壁中的蛋白质纤维的收缩创建。
The other mechanism is secretion of mucus by a row of pores around
the septum of the cell.
另一个机制是粘液分泌物通过一排气孔包围细胞的隔膜。
Some types, such as Nostoc, are only motile during certain stages of their life
cycle, when they produce a gliding dispersal stage known as hormogonia.
一些类型，像念珠藻属，仅仅在它们生命周期的某一阶段是运动的，在这一阶段它们产生被称为是藻殖段的滑行分散阶段。
Synechococcus also seems able to swim in liquid media without using flagella.
聚球藻属似乎没有使用鞭毛也能在液体介质中游动。
Until the use of 16S rRNA analysis established Cyanobacteria as a group within the Bacteria, they
were classified by botanists into about 150 genera and 1000 species based on morphological features
(Table 5.1).
直到16s rRNA作为细菌内的整体用途分析的确定，它们通过植物学家深入到基于形态学特征的150个属和1000个种类被分类(Table 5.1).
Subsequent phylogenetic analysis shows that these groupings are very unreliable and
many genera are polyphyletic.
后来系统的分析表露这些组群是非常靠不住的并且许多属是多元的。
Since bacteriologists can now grow many of the Cyanobacteria in pure
culture, analysis of biochemical characteristics and molecular features are taking over as a basis of
classification, and a major revision of the group is in progress.
既然细菌学家现在可以在纯培养中培育许多蓝藻细菌，生化特征的和细胞特征的分析作为分类的基础被掌握，并
且
这一种群的主要修正在进行中。
Pure culture studies show that the
physiological properties of Cyanobacteria are more variable than previously thought.
纯培养研究表明蓝藻细菌的生理特性比以前所想象的更为复杂（多变）。
Many are capable of anaerobic growth, some can use H2S, H2 or reduced organic compounds as electron
donors and some can be photoheterotrophic.
许多厌氧生长是可以的，一些可以利用H2S，H2或者减少有机化合物作为电子供体并且一些可以是光异养菌。
However, little is known about the significance of these
modes of nutrition in natural marine environments.
无论如何，在自然的海洋环境有关这些模式的重要性很少被知道。
5.4.3 Nitrogen fixation固氮作用
All major groups of marine Cyanobacteria contain members which fix atmospheric N2. Figure 4.5
shows an outline of the reactions involved in this process.
所有主要的海生蓝藻细菌种群包含固定大气中N2的成员。图4.5显示反应的轮廓涉及这一进程。
Table 5.1 Examples of marine Cyanobacteria海生的蓝藻细菌的例子
Order顺序 Features 特点 Major marine genera主要海生属
Chroococcales蓝球藻目 Unicellular or aggregates of single cells.单细胞或者单细胞的聚合体 May be motile Prochlorococcus可能是运动型的原绿球藻
Synechococcus聚球藻属
Synechocystis集胞藻属
Pleurocapsales宽球藻目 Aggregates of single cells.单细胞的聚合体 Reproduce by small spherical gliding
cells (baeocytes) formed by multiple fission通过由多重分裂形成的小球形的滑行细胞繁殖（复制）
Cyanocystis
Pleurocapsa宽球藻属
Oscillatorales Filamentous cells (trichome), often sheathed.Oscillatorales纤维状的细胞，时常被覆盖。 Intercalary binary
division at right angles to long axis.插入的二元分度由直角变为长轴。 Motile
Trichodesmium运动型束毛藻属
Lyngba
Nostocales Filamentous trichome with heterocysts Nostoc
StigonematalesBranching clusters, filamentous with heterocysts Mainly freshwater
or terrestrial念珠藻目纤维状毛状体和异形胞真枝藻目分支群组，丝状的异形胞主要的淡水的或者陆地的
The bond in molecular N2 is very
stable, and its reduction to ammonia is an extremely energy-demanding process, requiring 16
molecules of ATP for each molecule of N2 fixed.
氮分子的化学键十分稳定，它转变为氨是一个极其需要能量的过程，每分子N2固定需要16分子的ATP。
The key enzyme, nitrogenase, consists of two
separate protein components complexed with iron, sulfur and molybdenum. In the marine
environment, N2 fixation is carried out by a wide range of heterotrophic and autotrophic bacteria and
is of fundamental significance in primary production in the oceans (Chapter 9).
关键的酶，固氮酶，包含单独的结合铁，硫以及钼的蛋
白质成分。在海洋的环境，氮气的固定通过许多各种不同的非自养的和自养的细菌得以实现并且是海洋初级生产
的基本意义。
Most N2-fixers are anaerobic, but the Cyanobacteria are aerobic and, because the enzyme nitrogenase is highly O2-
sensitive, N2 fixation is often restricted to the night when no O2 is generated.
大部分的固氮菌是厌氧的，但是蓝藻细菌是需氧的，因为固氮酶对氧气是高度敏感的，氮气的固定常常被限制直到晚上没有氧气生成的时候得以继续。
Many of the more efficient N2-fixers contain differentiated cells known as heterocysts within the filament.
许多比较有效率的固氮菌包含分化型的细胞被称为具有长纤丝的异形胞。
Because the heterocysts contain no photosytem II, they provide an O2-free environment which protects the
enzyme nitrogenase.
因为异形胞不包含photosytem II，它们提供保护固氮酶的无氧环境。
However, one of the most prolific marine N2-fixers is Trichodesmium, which
does not contain heterocysts. Recently it has been shown that Trichodesmium is able to switch the
two processes of the O2-producing photosynthetic system and the O2-sensitive N2-fixing system on
and off over timescales of a few minutes.
无论如何，最丰富的海生固氮酶之一是不含异形胞的束毛藻属。最近它已经被显示出束毛藻属能够转变光合作用产氧体系和氧气敏感固氮体系这两种进程并且切断
几分钟的时间量程。
There also appears to be a spatial separation of O2
evolution and N2 fixation, because N2 fixation is limited to certain parts of the cell. Trichodesmium
forms dense filamentous masses which are responsible for large blooms, especially in tropical seas.
这也仿佛是氧气的变化和氮气的固定空间的分离，因为氮气固定被限制在细胞的某一部分。束毛藻属形成浓厚的细丝状的包块是多数的海藻的原因，尤其是在热带海洋中。
5.4.4 Prochlorococcus and Synechococcus原绿球藻和聚球藻属
Although many types of Cyanobacteria are found in marine environments, two genera dominate the
picoplankton in large areas of the Earth’s oceans, namely Synechococcus and Prochlorococcus.
虽然蓝藻细菌的许多类型是在海洋环境被发现的，两个属在地球海洋上的大规模区域的浮游微生物占优势地位，也就是原绿球藻和聚球藻属。
These organisms are major contributors to the carbon cycle through photosynthetic CO2 fixation, accounting
for between 15 and 40% of carbon input to ocean food webs. Prochlorococcus is a very small (about
0.6 μm diameter) cyanobacterium which was not discovered until 1988 (following the use of FCM),
despite the fact that it inhabits large parts of the oceans at a density between 105 and 106 ml?1,
making it the most abundant photosynthetic organism on Earth.
这些生物体是通过光合作用CO2固
定碳循环的主要贡献者，占了百分之十五到四十之间投入到海洋食物链的碳量。原球藻属是直到1988年才发现的最小的蓝藻菌。
尽管事实是它栖息于大部分海洋密度在105到106ml?1，使它成为了地球上最丰富的光合作用生物体。
Prochlorococcus is most abundant in
the region from 40°S to 40°N, temperature range 10°C to 33°C, to a depth of about 200 m.
Prochlorococcus contains modified forms of chlorophyll (divinyl chlorophylls a and b), but lacks
phycobilins.
原绿球藻在南纬40度到北纬40度之间，温度范围在10到30度之间，海洋深度200米左右分布最为丰富。原绿球藻包含叶绿素的改良型，但是缺乏藻胆素。
The photosynthetic apparatus seems to be adapted to allow Prochlorococcus to grow at
considerable depths, where the amount of light is very low (below 1% that at the surface). The small
cell size gives a large SA:V ratio, which helps Prochlorococcus obtain scarce nutrients in oligotrophic
ocean waters.
光合作用器官看起来像是被适应以允许原绿球藻在光照非常少的相当大的深度生长（表面低于百分之一）。小的细胞尺寸产生大的表面面积：体积比，
帮助原绿球藻在营养不足的海水中获得缺乏的营养物。
Other organisms with similar properties include Prochloron, which is an intracellular
symbiont of certain marine invertebrates.
其他的生物体拥有相似的特性包括原绿藻属，在海生无脊椎动物中是细胞内的共生体。
These organisms were originally placed in a group called
the prochlorophytes, but phylogenetic analysis shows that this is not a distinct lineage within the
Cyanobacteria.
这些生物体最初被放置于称作原绿生物的群中，但是系统的分析表明这同蓝藻细菌没有显著地世系。
Prochlorophytes appear to have evolved divinyl chlorophylls a and b, which allows
them to harvest longer wavelengths of blue light, which penetrate deeper waters.
原绿生物似乎有进化了的允许它们从穿透更深水的蓝光中获得较长波长的二乙烯基叶绿素a和b。
Indeed, studies on Prochlorococcus cultures and populations from the field have shown that there are two distinct
populations of ecotypes, which occupy different light niches. A high-light-adapted ecotype dominates
the top 100 m of water, which is characterized by high light flux and very low nutrient
concentrations.
的确，这一领域在原绿球藻文化以及种群的研究已经表明有两个显著的占据不同光段的生态类群。一种高度光适应的生态型在前100米的高亮度光通量和低营养的水中占优势。
The second ecotype thrives at depths of 80–200 m, which have low light intensity
but higher nutrient concentrations.
第二种生态型在80--200米的深度生长，这里有低的光强度但是有高营养浓度。
The two ecotypes have different ratios of chlorophyll
a2 to b2 and
differ in their optimal irradiances for photosynthesis. These significant differences in ecotype are
determined by genetic differences of only about 2% in 16S rRNA sequences.
这两种生态型有不同的叶绿素a2到b2的比率并且对光合作用来说拥有理想的光照度。这些生态型的显著性差异由仅仅大约百分之二的16srRNA序列的遗传偏差决定。
They should probably be assigned to separate species, because the two types differ markedly in the number of genes
encoding the light-harvesting complex. (See Box 5.1 for a discussion of the difficulties of species
definition based on 16S rRNA studies.)
它们大概应该归属于单独的种类，因为这两种类型在许多基于16S rRNA研究定义中有明显的不同。（参见框5.1基于16S研究物种定义困难的讨论）
The discovery of Prochlorococcus is also highly significant for evolutionary theory. It has been
thought for many years that the chloroplasts present today in algae and plants evolved from
Cyanobacteria in accordance with the endosymbiosis theory.
原绿球藻的发现对于进化论有重要意义。叶绿体现今出现在藻类和由蓝藻细菌进化来的植物与内共生学说一致已经被知道很多年。
Phylogenetic analyses suggest that prochlorophytes, despite resembling chloroplasts without phycobilins, are not the immediate ancestral
origin of the chloroplast. It is possible that the prochlorophytes and the rest of the
系统分析暗示原绿生物，尽管类似没有藻胆色素的叶绿体，并不是叶绿体最近的原始起源。它是可能的原绿生物和其余的叠层。
Figure 5.3
Stromatolites.
(a) Columnar build-ups in shallow water, Highborne Cay, Bahamas. (b) Vertical section
showing lamination; scale bar, 2 cm. From Reid et al. (2000), reproduced with permission, Nature-
Macmillan Ltd.
（a)在浅水的柱状堆起， Highborne Cay, Bahamas.(b)纵切面展示分层；测量条，2厘米。From Reid et al. (2000)，复制经过许可，Nature-
Macmillan Ltd.
Cyanobacteria may have evolved from ancestors that contained phycobilins and more than one type
of chlorophyll. Prochlorophytes may have lost their phycobilins and the other Cyanobacteria may have
lost their chlorophyll b during evolution, whilst the eukaryotic chloroplast evolved from the
hypothetical ancestor of both groups. We do not know when this divergence occurred.
蓝藻细菌包含藻胆色素和不止一种类型的叶绿素可能由祖先进化。在进化期间原绿生物可能已经失去了它们的藻胆色素以及其他的蓝藻细菌可能已经失去了它们的叶绿素b，
而真核生物的叶绿体由两个类群的假想祖先进化而来。
5.4.5 Microbial mats and stromatolites微生物的层次及构造
Cyanobacteria are especially important in the formation of microbial mats in shallow water. Complex
stratified communities of microorganisms develop at interfaces between sedi
ments and the overlying
water.
蓝藻细菌对浅水中微生物层次形成尤其重要。微生物复杂的分层群体在沉积物和和叠加的水之间的相互作用中发展。
Filamentous Cyanobacteria such as Phormidium, Oscillatoria and Lyngbya are often dominant
members of the biofilm in association with unicellular types such as Synechococcus and
Synechocystis.
纤维状蓝藻细菌像席藻属，颤藻和鞘丝藻经常是与单细胞类型像聚球藻属和集胞藻属联系的生物膜显性成员。
Steep concentration gradients of light, O2, H2S and other chemicals develop across
the biofilm. The mat becomes anoxic at night and H2S concentrations rise. Cyanobacteria (and other
motile bacteria in the biofilm) can migrate through the mat to find optimal conditions. Anoxygenic
phototrophs as well as aerobic and anaerobic chemoheterotrophs are also present.
急剧的光线，O2，H2S和其它化学品浓度梯度通过生物膜生长。在夜里垫子（mat）变为缺氧的而且H2S浓度升高。蓝藻细菌（和在生物膜上其他的运动型细菌）
可以通过垫子移动来寻找最适条件。不产氧的光养生物和需氧的一样而且厌氧的chemoheterotrophs也存在。
Stromatolites are fossilized microbial mats of filamentous prokaryotes and trapped sediment. These
ancient structures were widespread in shallow marine seas over three billion years ago. Ancient
stromatolites were probably formed by anoxygenic phototrophs, but modern stromatolites are
dominated by a mixed community of Cyanobacteria and heterotrophic bacteria.
叠层是石化的纤维状的原核生物和搜集沉淀物的微生物垫子。超过3亿年以前这些古老的结构广泛分布在浅海中。
古老的叠层大概是由不产氧的光养生物所形成，但是现在的叠层通过复杂的蓝藻细菌和异养细菌共生体控制。
Growth of modern marine stromatolites represents a dynamic balance between sedimentation and intermittent
lithification of cyanobacterial mats (Figure 5.3). Rapid sediment accretion occurs when the
stromatolite surfaces are dominated by pioneer communities of gliding filamentous Cyanobacteria.
During intermittent periods, surface films of exopolymer are decomposed by heterotrophic bacteria,
forming thin crusts of microcrystalline calcium carbonate. Other types of Cyanobacteria modify the
sediment, forming thicker stony plates.
现代的海生叠层生长代表沉淀和蓝藻垫子间歇的岩化的动态平衡。当叠层表面通过滑顺的细丝状蓝藻细菌先锋群落被控制，迅速的沉积增加发生。
在间歇周期期间，外聚合物表面薄膜通过异养细菌被分解，形成微晶的碳酸钙薄外壳。蓝藻细菌的其他类型修饰沉淀物，形成厚的石质平板。
5.5 The nitrifying bacteria硝化细菌
This term describes bacteria that grow using reduced inorganic nitrogen compounds as electron
donors. Marine examples, which are present
in suspended particles and in the upper layers of
sediments, include Nitrosomonas and Nitrosococcus (which oxidize ammonia to nitrite) and
Figure 5.4
Oxidation of ammonia by nitrifying bacteria.
这个术语描述了生长利用减少无机氮化合物作为电子供体。海洋的例子，存在于悬浮粒子及沉淀物上层，包括亚硝化单胞菌以及亚硝化球菌属（将氨氧化为亚硝酸盐）并且
通过硝化细菌氨的氧化。
Examples of marine genera known to carry out these
processes are shown. These reactions are energetically unfavorable and oxidation of 35 ammonia
molecules or 15 nitrite molecules is required to produce fixation of one molecule of carbon dioxide.
Nitrosobacter, Nitrobacter and Nitrococcus (which oxidize nitrite to nitrate). No organisms that can
carry out both reactions are known.
例如海洋属已知用来去执行这些进程被显示。这些反应是积极地不宜的而且35分子氨的氧化或是15分子亚硝酸盐需要用来固定一分子二氧化碳。
亚硝酸杆菌，硝化菌属和硝化球菌属（氧化亚硝酸盐到硝酸盐）。已知没有生物体可以完成两种过程。
The ammonia-oxidizers are obligate chemolithoautotrophs and
fix carbon via the Calvin cycle. The nitrite-oxidizers are usually chemolithoautotrophic, but can be
mixotrophic using simple organic compounds heterotrophically. Because of these activities, nitrifying
bacteria play a major role in nitrogen cycling in the oceans, especially in shallow coastal sediments
and beneath upwelling areas such as the Peruvian coast and the Arabian Sea.
氨氧化菌是天生的化能无机自养型而且通过卡尔文循环固定碳。亚硝酸盐氧化菌是自动的化能无机自养型，但是兼养的不是自养的利用简单的有机化合物。
因为这些活动，硝化细菌在海洋氮循环中扮演了重要的角色，尤其是在海岸沉积物中并且在上升流区域的下方，像秘鲁海岸和阿拉伯海。
Previously, nitrifying bacteria were classified mainly on morphological characteristics. However, 16S rRNA analysis shows
that they occur in several branches of the Proteobacteria, and one type, Nitrospira, forms a distinct
bacterial phylum. Members of the γ subdivision have been found only in marine environments. Like
the phototrophs, nitrifying bacteria have extensive internal structures in order to increase the surface
area of the membrane.
以前，硝化细菌主要根据形态学特点被分类。无论如何，16s rRNA分析表明它们发生在变形菌门的几个分支，并且一种类型，硝化螺菌属，形成了明显的细菌门。
r亚门的成员仅仅在海洋环境被发现。像光养生物，硝化细菌有广泛的内部结构为了增加膜的表面。
It is difficult to obtain estimates of the abundance and community structure of nitrifying bacteria.
Although most can be cultivated in the laboratory; the energetics of this mode of chemo
lithotrophy
mean that the bacteria grow slowly and are difficult to work with.
难以取得硝化细菌的群落结构丰度的预算。虽然大多数可以在实验室培养；但是无机化能营养这种能量模式意味着细菌缓慢地生长难以使用其进行（实验）工作。
Immunofluorescence methods
(Section 2.4) reveal that Nitrosococcus oceani and similar strains are widespread in many marine
environments, with worldwide distribution, at concentrations between 103 and 104 cells ml?1. This
organism is thought to be responsible for significant oxidation of ammonia in the open ocean.
Nitrospira also appears to be distributed worldwide.
免疫荧光方法显示亚硝化球菌属以及相似的菌株在许多海洋环境是广泛分布的，全世界的分布，在103-104细胞ml?1浓度之间。这种有机体
被认为是在露天海洋中氨的重大的氧化的原因。硝化螺菌属好像是分布全世界的。
Study of their activities and contribution to
nitrogen cycling is usually carried out using isotopic methods with 15 or 15 (Section 2.7.3) or
by using various inhibitors of nitrification enzymes (e.g. nitrapyrin inhibits ammonia monoxygenase).
Nitrification is a strictly aerobic process and sufficient O2 usually only penetrates a few millimeters
into sediments.
它们活动以及对氮循环的贡献的研究通常被执行使用15或15同位素的方法或者通过使用各种各样的硝化酶抑制剂（例如氨啶抑制氨一氧化物酶）。
硝化作用是严格的需氧过程并且足够的氧气通常仅仅渗透到沉积物几毫米。
Activity of burrowing worms can increase O2 availability to deeper levels of
sediments. Nitrification rates are high in waters where plant photosynthesis releases O2 and the
release of nitrate stimulates plant growth. This is of great importance in the productivity of seagrass
beds. The overall reactions for oxidation of ammonia to nitrite and its subsequent oxidation to nitrate
are shown in Figure 5.4.
挖掘蠕虫活动可以增加氧气可利用率到更深层次的沉积物中。硝化作用比率在水中是高的，水中植物光合作用释放氧气并且硝酸盐的释放刺激植物生长。
对海草床的生产力具有重要意义。氨氧化成硝酸盐的总反应以及它后来生成硝酸盐的氧化见图5.4.
5.6 Sulfur-and iron-oxidizing chemolithotrophs氧化硫以及铁的化能自养菌
5.6.1 Thiobacillus, Beggiatoa, Thiothrix, and Thiovulum
A wide range of Proteobacteria can grow chemolithotrophically using reduced sulfur compounds as a
source of electrons, leading to the formation of sulfate.
硫杆菌，贝日阿托氏菌，似硫细菌属，和卵硫细菌属
大多的变形菌门可以化能无机营养地利用减少的硫化物作为电子来源，导致硫酸盐的形成。