motile-30

运动这个英语单词怎么写

mot,mov,mob = to move（运动）

来源于拉丁语的mot,mov,mob它们是同源异形根，意为 to move。mov 来源于拉丁动词movere,mot来源于movere 的动名词词干，mob 是movere 的形容词性分词的词干。它们的同义词根有来源于拉丁语的migr和来源于希腊语的。

kine/cinema。

（*拉丁文movere(=to move),mobilis(=movable),motio(=movement) —— 英文根字典）

1.commotion（一起 com(=together) + mot(=move)）(com共同+motion动→大家一起动→动乱)。

n.骚动；动乱；暴乱

There was a huge commotion in the hall when Aunt Betty dropped a tray of drinks. 贝蒂姑妈弄掉一个饮料盘，大厅里一阵混乱。

2.motivate（使感动，使心动mot(=move)）(mot运动+ive……的→n.动机,目的 adj.发动的,运动的)。

vt.给予...动机；刺激；激发。

motivation n.刺激；推动。

motive n.动机；（文艺作品的）主题。

motiveless adj.毫无动机的。

The picture of the fat lady on my refrigerator motivates me not to eat. 贴在电冰箱上的胖女人图片促使我节食。

3.immoblie (im不+mobile[adj.可动的,活动的,运动的]→adj.不动的,固定的,静止的,不能移动的)（不能移动的im<in(=not) + mob(=move)）

adj.不能移动的，不动的；固定的。

immobilize v.使不能移动。

immobility n.不动，静止；固定。

A plaster cast holds a broken bone immobile,allowing it to heal. 石膏绷带固定的骨折的地方，以使其恢复。

4.demote (de向下+mot运动+e→向下动→降级) *de(=down)。

v.使降级

demoted adj.降级的。

5.emotion (e出+mot运动+ion名词后缀→动出[感情]) *e<ex(=out)。

n.感情，情绪；激动

betray one's emotion 流露感情。

6.emotional

adj.感情的，情绪的；易动情的；激起感情的。

emotionally adv.情绪上，感情上。

emotive adj.感情的；情绪的。

emotionless adj.没有感情的，冷漠的。

emotional appeal 情感诉求。

emotional woman 易动情的女子。

7.locomotion (loc(=to place) + -o-(起连接作用，有的书籍中叫中缀) + mot 移动 + -ion名词后缀 →从一个地方移动到另一个地方→运动，移动)。

n.运动，移动

8.locomotive

n.机车 adj.移动的，有移动力的 *loc(=to place)。

steam/diesel/electric locomotives 蒸汽/柴油/电力机车。

locomotive engineer 火车司机。

9.promote (pro向前+mot动→向前动→促进)。

v.使晋升，使晋级；推进，促进；发起 *pro(=forward,forth)。

He was promoted lieutenant colonel/to lieutenant colonel/to the rank of lieutenant colonel . 了晋升为陆军中校。

promote good feelings 增进好感。

promote a new business company 成立新公司。

10.promoter (同上，-er 后缀表示...的人，向前移动的人→促进者，助长者；提倡者等)。

n.促进者，助长者；提倡者，（企业的）发起人；（营业性体育比赛的）承办人 *pro(=forward,forth)。

11.promotion (同上)。

n. 晋极，晋升；发起；助长，推进；（通过宣传、广告等的）宣传；推销 *pro(=forward,forth)。

win/gain promotion 晋级，晋升。

promotion of a new commercial product /a new book 新商品/新书的推销、宣传。

sales promotion 促销。

12.remote (re回+mot运动+e→动回去→退回去→遥远的)。

adj.（时空上）遥运的；关系疏远地。

remote control 遥控。

remote sensing 遥感。

remote from the subject we are discussing 和我们所议论的主题关系甚远。

13.motif

n.（文艺作品等的）主题；（音乐的）乐旨，动机；基本图案；

14.motion (mot 移动 + ion后缀)。

n.运动，移动；动作，姿势（如手势、点头等）；动议，提议。

v.向...示意，向...打手势。

motionless adj.不动的，静止的。

motion sickness 晕船（或车）

graceful motions 优雅的举止。

on the motion of Mr.King 在金先生的动议下。

The motion was adopted/carried/rejected by a majority of six. 那项动议以六票的多数被采纳/通过/否决。

He motioned me out. 他示意我出去。

He motioned to me to come nearer. 他示意我走近一点。

15.motor (mot 移动 + or 名词后缀，既可以表示“人”，也可以表示“物”，在些表示“物”→ 能使移动的东西→ n. 马达；电动机等)。

n.发动机，马达；电动机；内燃机 adj.机动的；引起运动的；汽车（用）的 v.乘汽车，驾驶汽车。

motorize v.使（军队等）机动化。

electric motors 电动机。

motor vehicle 机动车（轿车、公共汽车、卡车等的总称）

16.motorist (mot + or + ist，这个单词构词结构为：词根 + or 名词后缀 + ist名词后缀(表示...人))。

n.汽车驾车者

17.motto

n.座右铭，箴言，格言；警句；（写在盾牌、纹章等的上的）铭词；（书籍扉页上或章节前引用的）题词。

18.mob (mob动→n.暴民,乌合之众[尤指暴力者] v.围攻,聚众闹事)。

n.乌合之众，暴徒；<贬> (the ~) 大众，民众；（犯罪者的）一伙，一群。

v.（人）蜂拥而入；（成群）袭击，围攻。

mobster n.暴徒，匪帮或流氓集团的一分子。

19.mobile

adj.移动的，可动的；易变的，善变的。

n.活动装置（可着气流活动）

mobility n.移动性 (mobile[adj.可动的,活动的,运动的]+ity性质→n.可动性,机动性,[阶层间的]流动性)。

20.mobilize (mobile[adj.可动的,活动的,运动的]+ize做→mobilize使[人]动→动员[入伍])。

v.（特指战时）动员；使流通；使松动。

mobilization n.动员；流通。

mobilization orders 动员令。

national mobilization 全国总动员。

21.automobile (auto自+mob动+ile物体→自动车→汽车)。

n.汽车 *auto(=self)。

22.demobilize (de去掉,反+mobilize动员→反过来动员→复员)*de(=reverse the action of )。

v.使退伍，使复员；遗散军队。

demob <口>= demobilize。

When do you get demobbed ?你什么时候退伍 ？

demobilization n.复员，遗散军队。

23.move (mov运动+e→n.&v.移动, 迁居, 步骤)。

v.（使）移动；搬家；使感动；提议；进展，进行，行动，采取措施；使排泄，通便。

n.（位置的）移动，行动；措施；（国际象棋等的）棋子的走法。

We are moving (house) next month. 我们下个月搬家。

move out /in 搬出去/搬进来。

We were all moved by her entreaties. 我们都被她的恳求感动了。

It was a moving sight. 这是令人感动的一幕。

be moved to tears 感动得流下了眼泪。

Mr.Chairman,i move that the money be used for library books.主席先生，我提议用这笔钱来为图书馆购买一些书籍。

Large enemy forces are on the move. 敌人的大军正在转移。

move towards settling the strike 制止罢工的措施。

It's your move. 该你走棋了。

24.movable

adj.活动的，可动的；（财产的）动产的；（节目）每年日期变化的。

n.(pl.)动产；可移动的东西。

movable feast 日期变化的宗教节日（如复活节等）

movable property 动产。

25.movement (mo=mov运动+ment表名词→时间移走)。

n.移动，运动，活动；（军队的）移动；机械装置；（政治、社会或思想）运动；（股票、市场等的）动向，变动；(pl.)行动，动静；（音乐）乐章；通便。

movementum n.运动量；要素；动力。

movement of heavenly bodies 天体的运行。

without movement 一动不动。

Labor Movement 工人运动。

26.mover

n.提议者，提案者

the prime/first mover 倡导者，发起人。

27.movie (mov移动 + -e后缀，胶片以每秒24格画面匀速转动产生逼真的动感→电影)。

n.电影；(the movies) 电影的放映；电影业。

movie fan / theater 影迷/电影院。

go to the movies 去看电影。

28.moving

adj.移动的；（使）感动的。

moving picture 电影。

moving sidewalk 活动式人行道。

29.remove

v.（使）移动；除去，撤走，脱掉；使离开；使退学；使免职。

n.移动；除去 *re(=back,away)。

removable adj.可免职的；可移动的；可去掉的。

remover n.搬运工；去除剂。

remove fears 赶走恐慌惧。

be removed from his post for acception bribes 他因受贿而被免职。

superfluous hair remover 脱毛剂。

30.removal

n.移动；除去 *re(=back)。

removal of furniture 搬运家具。

removal of dissatisfaction 消除不满。

31.mobocracy (mob 暴民（暴民都喜欢动，动武）(-o- 中缀) + cracy (=rule))。

n.暴民统治;暴民政治

32.mutiny (mut改变+iny→n.兵变;反抗 v.叛变)。

n.兵变;反抗

mutinous adj.反叛的；背叛的。

C结尾的单音节形容词，要有比较级的有哪些？

汉英释义我要报错运动

motion

movement

sports

athletics

exercise

▲折叠《新汉英大辞典》▼展开《新汉英大辞典》

运动 [yùn dòng]

{物} motion; movement; locomotion; travel: 。

例句： matter in motion;。

运动中的物质

rectilinear motion;。

直线运动

the accelerated motion;。

加速运动

wavy motion;

波状运动

an up-and-down motion;。

上下运动

circling motion;。

圆周运动

study the laws of motion;。

研究运动的规律

The piston moves by steam pressure.。

活塞在蒸汽压力下运动。

（体育活动） sports; athletics; exercise: 。

例句： outdoor sports;。

室外运动

athletic sports;。

体育运动

aquatic sports;。

水上运动

master of sports; sportsmaster;。

运动健将

Walking is also a form of exercise.。

散步也是一种运动。

（政治、文化、生产等活动） movement; campaign; drive: 。

例句： patriotic public health movement;。

爱国卫生运动

launch a mass movement;。

开展群众运动

peasant movement;。

农民运动

rectification campaign;。

整风运动

election campaign;。

竞选运动

The temperance [dry; anti-alcohol] movement revived in the city.。

这个城市的禁酒运动又活跃起来了。

{生理} motor

短语:

运动保健 sports health; 。

运动表象型 motile;

运动冰川 active glacier; 。

运动冰碛 flow till; 。

运动病 motion sickness; 。

运动波 kinematic wave; 。

运动不能 {生} akinesia; akinesis; acinesia; 。

运动不能性缄默症[哑症] akinetic mutism; 。

运动参数平滑 smooth of motion parameter; 。

运动测量学 kinesimeter; 。

运动常数 constant of motion; 。

运动场 athletic field; sports ground; playground; 。

运动成形切断术 cineplastics; 。

运动成形术 cineplasty; 。

运动池 hydrogymnasium; 。

运动尺度谱 scales of motion; 。

运动创伤 sports injury; 。

运动代谢 exercise metabolism; 。

运动单位 {解} motor unit; 。

运动倒错 parakinesis; parakinesia; paracinesis; paracinesia; 。

运动点 motor point; 。

运动定律 law of motion; 。

运动短裤 gym shorts; 。

运动缎 sport satin; 。

运动对偶 kinematic pair; 。

运动法 method of movement; 。

运动反向 reversing of motion; 。

运动范围不足 hypometria; 。

运动范围过度 hypermetria; 。

运动方程式 {量子} equation of motion; equation governing the motion; 。

运动方向 direction of motion; direction of movement; 。

运动放大 kinematic gain; 。

运动飞机 sport plane; 。

运动分析器 motion analyzer; 。

运动服装 sportswear; 。

运动副 pair;

运动感觉缺失 akinesthesia; 。

运动根 {生} motor root; 。

运动功能减退 hypokinesia; hypocinesia; hypocinesis; 。

运动功能减退综合征{医} hypokinetic syndrome; 。

运动功能亢进 hyperkinesia; hypercinesia; 。

运动共济失调 locomotor ataxia; 。

运动关节法 joint-moving manipulation; 。

运动规律 characteristics of motion; 。

运动过度 hyperkinesia; hypercinesia; 。

运动过敏 exercise allergy; 。

运动过强 hypermotility; 。

运动后尿胆素原尿 postexercise urobilinogenuria; 。

运动后效 motion after affect; 。

运动机件 moving parts; {钟} motion work; 。

运动机能 motor function; 。

运动机制 locomotory mechanism; 。

运动技术 telemechanics; 。

运动茄克衫 bi-swing; 。

运动减弱 hypomotility; 。

运动健将 master of sports; 。

运动节食疗法 terrain-cure; 。

运动精度 kinematic accuracy; 。

运动静力学 kinetostatics; 。

运动空间 space;

（类似灯笼裤的）运动裤 knickers; fours; 。

运动力 motoricity; 。

运动力矩 motoring torque; 。

运动链 kinematic link; 。

运动链系 kinematic chain; 。

运动疗法 kinesiatrics; cinesiatrics; kinesitheraphy; kinetotherapy; kinesipathy; exercise therapy; 。

运动流度 kinematic fluidity; 。

运动论 kinematics; phoronomy; 。

运动密度测定法 kinedensigraphy; 。

运动模拟器 motion simulator; 。

运动模型 motion model; 。

运动目标电子探测器 petoscope; 。

运动能力 locomotivity; trafficability; kinetism （肌肉）; 。

运动能量 kinergety; 。

运动呢 sportex;

运动皮质 motor cortex; 。

运动频谱 dynamic spectrum; 。

运动群 groups of motion; 。

运动期{摄} moving period; 。

运动器官 locomotive organ; 。

运动器械 exerciser; 。

运动枪 sporting rifle; 。

运动枪弹 sporting cartridge; 。

运动区 {解} motor area; 。

运动群 groups of motion; 。

运动赛车 sport-racing car; 。

运动筛 moving screen; 。

运动伞 sport parachute; 。

运动衫裤 gym outfit; 。

运动上衣（茄克） blazer; 。

运动神经 motor nerve; 。

运动（性）神经机能病 cinesioneurosis; 。

运动神经末梢 motor nerve ending; 。

运动神经皮质 motor cortex; 。

运动神经束 motor tract; 。

运动神经细胞 motor nerve cells; 。

运动神经纤维 motor fibre; 。

运动神经元 motor neuron; motoneuron; 。

运动失调 ataxia; dysergia; 。

运动时 movement time; 。

运动势 kinetic-potential; 。

运动试验 exercise test; 。

运动试验器 ergometer; 。

运动说 kinematical theory; 。

运动速度 pace;

运动算子 kinematic operator; 。

运动特性 kinetic characteristic; motion characteristic; 。

运动提前量 {军} kinetic lead; 。

运动体型 athletic type; 。

运动通信卫星 moving communication satellite; 。

运动图 motion diagram; 。

运动袜[长统袜] hoes; 。

运动物体 mobile;

运动误差 kinematic error; 。

运动系统 {生理} motor system; 。

运动系统疾病 motor system disease; 。

运动限度 limitation of the movement; 。

运动线 line of motion; 。

运动相对性宇宙论 kinematical cosmology; 。

运动相似 kinematic similitude; 。

运动鞋 sport footwear; 。

运动心理学 sports psychology; 。

运动循环 cycle of motion; 。

运动医学 sports medicine; 。

运动抑制 motorial inhibition; 。

运动因果错觉 ampliation; 。

运动元件 {工} motor element; 。

运动原 motor;

运动障碍 dyskinesia; dyscinesia; kinesipathy; 。

运动中枢 motor center; motorium; {动} motor area; motor cortex; 。

运动中心 centre of motion; 。

运动终板 motor end plate; 。

运动终末徐缓 bradyteleokinesis; bradyteleocinesia; 。

运动周期 period of motion; 。

运动状态 state of motion; 。

运动阻力 resistance to motion; 。

运动坐标 coordinates of motion 。

运动 [yùn dong]

arrange things or get things done through pull 。

以上来源于：《新汉英大辞典

动纤毛 静纤毛的区别

如 nice的比较级是nicer。

希望对你有帮助!

急求关于海洋的介绍（英语），快点，在晚上9点前弄好

纤毛可分为两种型态，一种称为运动纤毛（motile cilia），能够长久地向同一方向运动。另一种则是非运动纤毛（non-motile cilia），一般用作感应胞器。

下面是英文的解释（摘自维基百科）更详细。

Motile cilia

Larger eukaryotes, such as mammals, have motile cilia as well. Motile cilia are usually present on a cell's surface in large numbers and beat in coordinated waves.。

Primary/Immotile cilia。

In humans, primary cilia are found on nearly every cell in the body.[2]。

两者的一个简短的比较：

In comparison to motile cilia, non-motile (or primary) cilia usually occur one per cell; nearly all mammalian cells have a single non-motile primary cilium. In addition, examples of specialized primary cilia can be found in human sensory organs such as the eye and the nose:。

999 乘90等于什么?

ocean, interconnected mass of saltwater covering 70.78% of the surface of the earth, often called the world ocean. It is subdivided into four (or five) major units that are separated from each other in most cases by the continental masses. See also oceanography.。

The World Ocean。

Of the major units that comprise the world ocean, three—the Atlantic, Indian, and Pacific oceans—extend northward from Antarctica as huge “gulfs” separating the continents. The fourth, the Arctic Ocean, nearly landlocked by Eurasia and North America and nearly circular in outline, caps the north polar region. The Southern Ocean (also called the Antarctic Ocean) is now often considered a fifth, separate ocean, extending from the shores of Antarctica northward to about 60°S. The major oceans are further subdivided into smaller regions loosely called seas, gulfs, or bays. Some of these seas, such as the Sargasso Sea of the North Atlantic Ocean, are only vaguely defined, while others, such as the Mediterranean Sea or the Black Sea, are almost totally surrounded by land areas. Large and totally landlocked saltwater bodies such as the Caspian Sea are actually salt lakes.。

The boundaries between oceans are usually designated by the continental land masses bordering them or by ridges in the ocean floor, which also serve as geographic boundaries. Where these features are absent (such as the ill-defined northern boundary of the Antarctic Ocean), the boundary is somewhat arbitrarily fixed by fluctuating zones of opposing currents that act as partial barriers to the mixing of waters between the two adjacent oceans.。

The oceans are not uniformly distributed on the face of the earth. Continents and ocean basins tend to be antipodal, or diametrically opposed to one another, i.e., continents are found on the opposite side of the earth from ocean basins. For example, Antarctica is antipodal to the Arctic Ocean; Europe is opposed by the South Pacific Ocean. Furthermore, over two thirds of the earth's land area is found in the Northern Hemisphere, while the oceans comprise over 80% of the Southern Hemisphere.。

The world ocean has an area of about 361 million sq km (139,400,000 sq mi), an average depth of about 3,730 m (12,230 ft), and a total volume of about 1,347,000,000 cu km (322,280,000 cu mi). Each cubic mile of seawater weighs approximately 4.7 billion tons and holds 166 million tons of dissolved solids. One of the most unique and intriguing aspects of ocean water is its salinity, or dissolved salt content. The measurement of salinity is essentially the determination of the amount of dissolved salts in 1 kg of ocean water and is expressed in parts per thousand (‰). Ocean salinities commonly range between 33 ‰ to 38 ‰, with an average of about 35 ‰. Thirty-five parts per thousand salinity is equivalent to 3.5% by weight. Six elements (chlorine, sodium, magnesium, sulfur, calcium, and potassium) constitute over 90% of the total salts dissolved in the oceans. Pressure in the ocean waters increases with increasing depth due to the weight of the overlying water. The pressure increases at the rate of 1 atmosphere for every 10 m (33 ft) of depth (1 atm=15 lb per sq in. or 1,016 dynes per sq cm). The average temperature of the oceans is 3.9°C (39°F).。

It now appears that the waters making up the present oceans (and the gases that make up the present atmosphere) were not of cosmic origin, i.e., were not present in the primordial atmosphere. Instead, they were derived from the interior of the earth sometime in the first one or two billion years after the earth's formation. It is now also generally accepted that a new ocean crust has been forming more or less continuously for at least the past 200 million years through a process of volcanic activity along the midocean ridge system (see seafloor spreading), which consists of a series of underwater mountains. On the basis of present knowledge it seems highly probable that all ocean waters and atmospheric gases were gradually released by the separation of these volatile components from the silicate rocks of the crust and upper mantle through volcanic activity. (Molten lava is known to contain appreciable amounts of water and other volatiles that are released upon solidification.) With the passage of time, water released by volcanic activity gradually filled oceanic depressions.。

Continental Shelves, Slopes, and Rises。

Virtually all continents are surrounded by a gently sloping submerged plain called the continental shelf, which is an underwater extension of the coastal plain. The continental shelves are the regions of the oceans best known and the most exploited commercially. It is this region where virtually all of the petroleum, commercial sand and gravel deposits, and fishery resources are found. It is also the locus of waste dumping. Changes in sea level have alternatingly exposed and inundated portions of the continental shelf. Continental shelves vary in width from almost zero up to the 1,500-km-wide (930-mi) Siberian shelf in the Arctic Ocean. They average 78 km (48 mi) in width. The edge of the shelf occurs at a depth that ranges from 20 to 550 m (66 to 1,800 ft), averaging 130 m (430 ft). The shelves consist of vast deposits of sands, muds, and gravels, overlying crystalline rocks or vast thicknesses of consolidated sedimentary rocks. Although there is a great variation in shelf features, nonglaciated shelves are usually exceptionally flat, with seaward slopes averaging on the order of 205 m per km (10 ft per mi), or less than 1° of slope. The edge of the shelf, called the shelf break, is marked by an abrupt increase in slope to an average of about 4°.。

The continental slopes begin at the shelf break and plunge downward to the great depths of the ocean basin proper. Deep submarine canyons, some comparable in size to the Grand Canyon of the Colorado River, are sometimes found cutting across the shelf and slope, often extending from the mouths of terrestrial rivers. The Congo, Amazon, Ganges, and Hudson rivers all have submarine canyon extensions. It is assumed that submarine canyons on the continental shelf were initially carved during periods of lower sea level in the course of the ice ages. Their continental slope extensions were carved and more recently modified by turbidity currents—subsea “landslides” of a dense slurry of water and sediment.。

Many continental slopes end in gently sloping, smooth-surfaced features called continental rises. The continental rises usually have an inclination of less than 1/2°. They have been found to consist of thick deposits of sediment, presumably deposited as a result of slumping and turbidity currents carrying sediment off the shelf and slope. The continental shelf, slope, and rise together are called the continental margin.。

Trenches, Plains, and Ridges。

One of the most surprising findings of the early oceanographers was that the deepest parts of the oceans were not in the centers, as they had expected, but were in fact quite close to the margins of continents, particularly in the Pacific Ocean. Further exploration showed that these deeps were located in long V-shaped trenches bordering the seaward edge of volcanic island arcs. These trenches are one of the most striking features of the Pacific floor. Trenches virtually encircle the rim of the Pacific basin. The trenches have lengths of thousands of kilometers, are generally hundreds of kilometers wide, and extend 3 to 4 km (1.9–2.5 mi) deeper than the surrounding ocean floor. The greatest ocean depth has been sounded in the Challenger Deep of the Marianas Trench, a distance of 10,911 m (35,798 ft) below sea level.。

The deep ocean floor begins at the seaward edge of the continental rise or marginal trench, if one is present, and extends seaward to the base of the underwater midocean mountains. Many relief features of great importance are present in this region. Vast abyssal plains cover significant portions of the deep ocean basin. Such plains are occasionally broken by low, oval-shaped abyssal hills. The abyssal plains cover about 30% of the Atlantic and nearly 75% of the Pacific ocean floors. They are among the flattest portions of the earth's crust and appear to be formed by the deposition of fine sediment carried by turbidity currents that have covered and smoothed out irregularities in the ocean floor.。

One of the most significant features of the ocean basins is the midocean ridge. First discovered in the Atlantic Ocean on the Challenger expedition, its relief features were further investigated during the German Meteor expedition of 1925–26. By the early 1960s it had been confirmed that the Mid-Atlantic Ridge was only part of a continuous feature that extended 55,000 km (34,000 mi) through the Atlantic, Indian, South Pacific, and Arctic oceans. The ridge is a broad bulge in the ocean floor that rises 1 to 3 km (0.6–2 mi) above the adjacent abyssal plains. It has a variable width averaging more than 1,500 km (c.900 mi). It is crossed by a number of fracture zones (transform faults) and displays a deep rift 37 to 48 km (23–30 mi) wide and about 1.6 km (1 mi) deep at its very crest.。

Relationship of the Ocean and the Atmosphere。

The atmosphere affects the oceans and is in turn influenced by them. The action of winds blowing over the ocean surface creates waves and the great current systems of the oceans. When winds are strong enough to produce spray and whitecaps, tiny droplets of ocean water are thrown up into the atmosphere where some evaporate, leaving microscopic grains of salt buoyed by the turbulence of the air. These tiny particles may become nuclei for the condensation of water vapor to form fogs and clouds.。

In turn, the oceans act upon the atmosphere—in ways not clearly understood—to influence and modify the world's climate and weather systems. When water evaporates, heat is removed from the oceans and stored in the atmosphere by the molecules of water vapor. When condensation occurs, this stored heat is released to the atmosphere to develop the mechanical energy of its motion. The atmosphere obtains nearly half of its energy for circulation from the condensation of evaporated ocean water.。

Because the oceans have an extremely high thermal capacity when compared to the atmosphere, the ocean temperatures fluctuate seasonally much less than the atmospheric temperature. For the same reason, when air blows over the water, its temperature tends to come to the temperature of the water rather than vice versa. Thus maritime climates are generally less variable than regions in the interiors of the continents.。

The relationships are not simple. The pattern of atmospheric circulation largely determines the pattern of oceanic surface circulation, which in turn determines the location and amount of heat that is released to the atmosphere. Also, the pattern of atmospheric circulation determines in part the location of clouds, which influences the locations of heating of the ocean surface.。

Currents and Ocean Circulation。

Surface Circulation。

The surface circulation of the oceans is intimately tied to the prevailing wind circulation of the atmosphere (see wind). As the planetary winds flow across the water, frictional stresses are set up which push huge rivers of water in their path. The general pattern of these surface currents is a nearly closed system of currents, called gyres, which are approximately centered on the horse latitudes (about 30° latitude in both hemispheres). Major circulation of water in these gyres is clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. In the North Pacific and North Atlantic oceans, smaller counterclockwise gyres are developed partly due to the presence of the continents. These are centered on about 50°N lat. The most dominant current in the Southern Ocean is the West Wind Drift, which circles Antarctica in an easterly direction. The northern and southern hemispheric gyres are divided by an eastward flowing equatorial countercurrent, which essentially follows the belt of the doldrums. This countercurrent is caused by the return flow of water piled up along the eastward portion of the equatorial seas, and its return flow is uninhibited by the weak and erratic winds of the doldrums. Analysis of current records shows that a number of major currents, such as the Gulf Stream, have strong fast-moving currents beneath them trending in the opposite direction to the surface current. Such undercurrents, or countercurrents, appear to be as important and pervasive as the surface currents. In 1952 the Cromwell current was found flowing eastward beneath the south equatorial current of the Pacific. In 1961 a similar current was discovered in the Atlantic. See also tide.。

Thermohaline Circulation。

Thermohaline circulation refers to the deepwater circulation of the oceans and is primarily caused by differences in density between the waters of different regions. It is mainly a convection process where cold, dense water formed in the polar regions sinks and flows slowly toward the equator. Most of the deep water acquires its characteristics in the Antarctic region and in the Norwegian Sea. Antarctic bottom water is the densest and coldest water in the ocean depths. It forms and sinks just off the continental slope of Antarctica and drifts slowly along the bottom as far as the middle North Atlantic Ocean, where it merges with other water. The circulation of ocean waters is vitally important in dispersing heat energy around the globe. In general, heat flows toward the poles in the surface currents, while the displaced cold water flows toward the equator in deeper ocean layers.。

The Ocean as a Biological Environment。

The oceans hold the answers to many important questions about the development of the earth and the history of life on earth. For instance, within the rocks and sediment of the ocean floors the geological history of the earth is recorded. Fossils in this sediment record a portion of the biological history of the earth at least back to the Jurassic period, which ended about 140,000,000 years ago. The first appearance of life on the earth is thought to have occurred in the oceans 2 or 3 billion years ago. The modern marine environment is divided into two major realms, the benthic and the pelagic, based upon the ecological characteristics and marine life associated with them. See also marine biology.。

The Benthic Realm。

The benthic realm refers to the floor of the oceans, extending from the high tide line to the greatest ocean depths. The organisms that live in or on the bottom are called benthos. The benthic realm is subdivided on the basis of depth into the littoral zone, which extends from high tide to a depth of about 200 m (660 ft), and the deep-sea realm. The benthic life forms are both sessile (attached) and motile (mobile). They are distributed from near-shore littoral regions to the ocean depths and play an important role in the food chain. Some benthonic life forms live by predation, others sift organic matter from the water, and others scavenge the bottom for organic debris that has settled there. Benthonic plants can live only in the euphotic zone, the uppermost 100–200 m (330–660 ft) of the ocean, where sunlight penetrates. Benthonic animals that live below the euphotic zone often must depend on the rain of organic debris from above to supply their food needs, and thus the deep regions of the benthic realm are not highly populated except in the areas around hydrothermal vents where chemosynthesis provides an alternative food source.。

The Pelagic Realm。

The pelagic realm consists of all of the ocean water covering the benthic realm. It is divided horizontally into the neritic, or fertile near-shore, province and the oceanic province. Vertically it is divided into the euphotic, or photic, zone and the aphotic (without sunlight) zone. Drifting, free-floating organisms, called plankton, and organisms with poor mobile ability populate the euphotic zone. Most plankton are microscopic or near-microscopic in size. Phytoplankton are photosynthetic bacteria (cyanbacteria) and floating algae, such as diatoms, dinoflagellates, and coccolithopores. Heterotrophic plankton (zooplankton) are floating animals and protozoans of the sea and rely on the phytoplankton as food sources. Foraminifera and radiolaria are the dominant protozoan zooplankton that secrete tests (shells), which become incorporated into the sediment of the ocean floor. Many juvenile forms of swimmers (such as shrimp) or bottom dwellers (such as barnacles) pass through a planktonic phase. Marine organisms capable of self-locomotion are called nektonic life forms. Fish, squid, and whales are examples of marine nekton.。

Importance of the Ocean。

Throughout history humans have been directly or indirectly influenced by the oceans. Ocean waters serve as a source of food and valuable minerals, as a vast highway for commerce, and provide a place for both recreation and waste disposal. Increasingly, people are turning to the oceans for their food supply either by direct consumption or indirectly by harvesting fish that is then processed for livestock feed. It has been estimated that as much as 10% of human protein intake comes from the oceans. Nevertheless, the food-producing potential of the oceans is only partly realized. Other biological products of the oceans are also commercially used. For example, pearls taken from oysters are used in jewelry, and shells and coral have been widely used as a source of building material.。

Ocean water is processed to extract commercially valuable minerals such as salt, bromine, and magnesium. Although nearly 60 valuable chemical elements have been found dissolved in ocean water, most are in such dilute concentrations that commercial extraction is not profitable. In a few arid regions of the world, such as Ascension Island, Kuwait, and Israel, ocean water is desalinated to produce freshwater.。

The shallow continental shelves have been exploited as a source of sands and gravels. In addition, extensive deposits of petroleum-bearing sands have been exploited in offshore areas, particularly along the Gulf and California coasts of the United States and in the Persian Gulf. On the deep ocean floor manganese nodules, formed by the precipitation of manganese oxides and other metallic salts around a nucleus of rock or shell, represent a potentially rich and extensive resource. Research is currently being conducted to explore nodule mining and metallic extraction techniques. Ocean water itself could prove to be a limitless source of energy in the event that nuclear fusion reactors are developed, since the oceans contain great quantities of deuterium.。

The oceans also have become more important for recreational use, as each year more people are attracted to the sports of swimming, fishing, scuba diving, boating, and waterskiing. Ocean pollution, meantime, has escalated dramatically as those who use the oceans for recreational and commercial purposes, as well as those who live nearby, have disposed of more and more wastes there .。

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