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  • 海浪的侵蚀和沉积

    Lesson Objectives
    ::经验教训目标

    • Explain how waves cause erosion of shorelines.
      ::解释海浪如何侵蚀海岸线。
    • Describe features formed by wave deposition.
      ::描述波浪沉降所形成的特征。
    • Identify ways to protect shorelines from wave erosion.
      ::确定保护海岸线不受波浪侵蚀的方法。

    Lesson Vocabulary
    ::词汇表课程

    • barrier island 
      ::隔离墙岛
    • breakwater
      ::断裂断裂断裂
    • groin
      ::腹股沟
    • longshore drift
      ::长岸漂流
    • sandbar
      ::沙巴沙巴
    • sea arch
      ::海洋拱门
    • sea stack
      ::海堆堆堆
    • spit
      ::喷口

    Introduction
    ::导言

    Have you ever stood on a sandy ocean beach and let the waves wash over your feet? If you have, then you probably felt the sand being washed out from under your feet by the outgoing waves. This is an example of wave erosion. What are waves? Why do they cause erosion? And what happens to the sand that waves wash away from the beach?
    ::你曾经站在沙滩上,让海浪冲洗你的脚吗?如果你是,你或许觉得海浪从你的脚下冲走沙子,那是波浪侵蚀的典型。海浪是什么?海浪为什么造成侵蚀呢?海浪从海滩冲走的沙子呢?

    What Are Waves?
    ::"浪潮"是什么?

    Waves are the way energy travels through matter. Ocean waves are energy traveling through water. They form when wind blows over the surface of the ocean. Wind energy is transferred to the sea surface. Then, the energy is carried through the water by the waves.  Figure   shows ocean waves crashing against rocks on a shore. They pound away at the rocks and anything else they strike.
    ::海浪是能量通过物质流动的方式。海洋波浪是能量通过水流流动的。当风吹过海洋表面时,它们形成。风能被转移到海面。然后,能量通过海浪从水中传过。图显示海浪撞击海岸上的岩石,它们撞击岩石和其他东西。

    lesson content
     
    Ocean waves transfer energy from the wind through the water. This gives waves the energy to erode the shore.

    Three factors determine the size of ocean waves:
    ::海洋波浪大小由三个因素决定:

    1. The speed of the wind
      ::风速的风速
    1. The length of time the wind blows
      ::风吹的时长
    1. The distance the wind blows
      ::风吹的距离

    The faster, longer, and farther the wind blows, the bigger the waves are. Bigger waves have more energy.
    ::越快,越长,风越远,海浪就越大。更大的海浪有更大的能量。

    Wave Erosion
    ::波浪侵蚀

    Runoff, streams, and rivers carry sediment to the oceans. The sediment in ocean water acts like sandpaper. Over time, the sediment in waves erodes the shore. The bigger the waves are, and the more sediment they carry, the more erosion they cause.
    ::流出、流流和河流将沉积物带入海洋。海水中的沉积物会像沙纸一样作用。随着时间推移,海浪中的沉积物会侵蚀海岸。海浪越大,所携带的沉积物越多,它们造成的侵蚀就越大。

    Landforms From Wave Erosion
    ::来自波浪侵蚀的地面形态

    Erosion by waves can create unique landforms ( Figure  ).
    ::海浪侵蚀可产生独特的地表形态(图 )。

    • Wave-cut cliffs form when waves erode a rocky shoreline. They create a vertical wall of exposed rock layers.
      ::当波浪侵蚀岩石海岸线时,波断悬崖形成,它们形成一面暴露岩层的垂直墙壁。
    • Sea arches  form when waves erode both sides of a cliff. They create a hole in the cliff.
      ::海浪侵蚀悬崖两侧时形成海拱,在悬崖上造成一个洞。
    • Sea stacks  form when waves erode the top of a sea arch. This leaves behind pillars of rock.
      ::海浪侵蚀海拱顶端时形成海堆,留下岩石的柱子。
    lesson content
     
    Over millions of years, wave erosion can create wave-cut cliffs (A), sea arches (B), or sea stacks (C).

    Wave Deposition
    ::波波沉积

    Eventually, the sediment in ocean water is deposited. Deposition occurs where waves and other ocean motions slow. The smallest particles, such as silt and clay, are deposited away from the shore. This is where water is calmer. Larger particles are deposited on the beach. This is where waves and other motions are strongest.
    ::最终, 海水中的沉积物被沉积。 沉积发生于海浪和其他海洋运动缓慢的地方。 最小的粒子, 如淤泥和粘土, 被沉积在岸边。 这是水比较平静的地方。 更大的粒子被沉积在海滩上。 这是海浪和其他运动最强的地方 。

    Beaches
    ::海滩

    In relatively quiet areas along a shore, waves may deposit sand. Sand forms a beach, like the one in  Figure  . Many beaches include bits of rock and shell. You can see a close-up photo of beach deposits in  Figure  .
    ::在相对安静的海岸地区,海浪可能沉积沙沙。沙沙形成海滩,如图中的沙滩。许多海滩包括岩石和贝壳。你可以看到图中海滩沉积的特写照片。

    lesson content
     
    Sand deposited along a shoreline creates a beach.
    lesson content
     
    Beach deposits usually consist of small pieces of rock and shell in addition to sand.

    Longshore Drift
    ::远岸漂流

    Most waves strike the shore at an angle. This causes  longshore drift . Longshore drift moves sediment along the shore. Sediment is moved up the beach by an incoming wave. The wave approaches at an angle to the shore. Water then moves straight offshore. The sediment moves straight down the beach with it. The sediment is again picked up by a wave that is coming in at an angle. This motion is show in  Figure  .
    ::大部分海浪从一个角度撞击海岸。 这导致远岸漂移。 远岸漂移的沉积物沿着海岸移动。 沉积会通过一个流入的波移到海滩上。 海浪会从一个角度走向海岸。 水会直接移到岸边。 沉积物会直接沿着海滩直移到海边。 沉积物会再次被一个角度进入的海浪吸收。 此运动在图中显示 。

    lesson content
     
    Longshore drift carries particles of sand and rock down a coastline.

    Landforms Deposited by Waves
    ::波浪所沉积的土地形态

    Deposits from longshore drift may form a spit. A  spit  is a ridge of sand that extends away from the shore. The end of the spit may hook around toward the quieter waters close to shore. You can see a spit in  Figure  .
    ::长岸漂流的矿床可能形成唾液。 唾液是远离海岸的沙脊。 唾液的尽头可能缠绕到海岸附近的宁静水域。 您可以在图中看到唾液 。

    lesson content
     
    Spit from Space. Farewell Spit in New Zealand is clearly visible from space. This photo was taken by an astronaut orbiting Earth.

    Waves may also deposit sediments to form  sandbars  and  barrier islands . You can see examples of these landforms in  Figure  .
    ::海浪还可能沉积沉积,形成沙条和屏障岛。

    lesson content
     
    Wave-Deposited Landforms. These landforms were deposited by waves. (A) Sandbars connect the small islands on this beach on Thailand. (B) A barrier island is a long, narrow island. It forms when sand is deposited by waves parallel to a coast. It develops from a sandbar that has built up enough to break through the water's surface. A barrier island helps protect the coast from wave erosion.

    Protecting Shorelines
    ::保护海岸线

    Shores are attractive places to live and vacation. But development at the shore is at risk of damage from waves. Wave erosion threatens many homes and beaches on the ocean. This is especially true during storms, when waves may be much larger than normal.
    ::海岸是居住和度假的有吸引力的地方。 但海岸的发展面临海浪破坏的风险。 海浪侵蚀威胁着海洋上的许多家园和海滩。 在风暴期间尤其如此,因为海浪可能比正常大得多。

    Breakwaters
    ::隔水

    Barrier islands provide natural protection to shorelines. Storm waves strike the barrier island before they reach the shore. People also build artificial barriers, called  breakwaters . Breakwaters also protect the shoreline from incoming waves. You can see an example of a breakwater in  Figure  . It runs parallel to the coast like a barrier island.
    ::屏障岛屿为海岸线提供自然保护。 风暴波在到达海岸之前就袭击了屏障岛屿。 人们还建造了人工屏障,称为防波堤。 断层水域也保护海岸线免受波浪的侵袭。 您可以在图中看到断层水的例子。 它与海岸平行,就像一个屏障岛。

    lesson content
     
    A breakwater is an artificial barrier island. How does it help protect the shoreline?

    Groins
    ::农村

    Longshore drift can erode the sediment from a beach. To keep this from happening, people may build a series of groins. A  groin  is a wall of rocks or concrete that juts out into the ocean perpendicular to the shore. It stops waves from moving right along the beach. This stops the sand on the up-current side and reduces beach erosion. You can see how groins work in  Figure  .
    ::长岸漂流会侵蚀海滩上的沉积物。 为了防止这种情况发生, 人们可能会建立一系列的腹股沟。 腹股沟是一块岩石或混凝土的墙壁, 形成与海岸垂直的海洋。 它能阻止海浪沿着海滩移动。 这可以阻止沙子在上边的沙子, 减少海滩侵蚀。 您可以看到图中的小股沟是如何工作的 。

    lesson content
     
    A groin is built perpendicular to the shoreline. Sand collects on the up-current side.

    Lesson Summary
    ::经验教训摘要

    • Ocean waves are energy traveling through water. They are caused mainly by wind blowing over the water.
      ::海洋波浪是贯穿水面的能量,主要是由风吹到水面造成的。
    • Sediment in ocean water acts like sandpaper. Over time, it erodes the shore. It can create unique landforms, such as wave-cut cliffs, sea arches, and sea stacks.
      ::海水中沉积的沉积物就像砂纸一样。随着时间的推移,它侵蚀了海岸。它可以创造独特的陆地形态,如波断悬崖、海拱和海堆。
    • Deposits by waves include beaches. They may shift along the shoreline due to longshore drift. Other wave deposits are spits, sand bars, and barrier islands.
      ::海浪的沉积层包括海滩,它们可能由于海岸的漂移而沿着海岸线移动。 其他的波沉积层包括唾液、沙条和屏障岛屿。
    • Breakwaters are structures that protect the coast like barrier islands. Groins are structures that help prevent longshore drift from eroding a beach.
      ::突破水是保护海岸的结构,像保护屏障岛屿一样。 沟渠是有助于防止海滩被岸外漂流侵蚀的结构。

    Lesson Review Questions
    ::经验回顾问题

    Recall
    ::回顾

    1. What are waves?
      ::什么是波浪?
    1. How do ocean waves cause erosion?
      ::海浪如何造成侵蚀?
    1. Identify three types of landforms created by wave erosion.
      ::查明因波浪侵蚀而形成的三种土地形态。
    1. What is a spit? How does it form?
      ::吐口水是什么 它是怎样形成的?

    Apply Concepts
    ::应用概念

    1. Create a diagram to illustrate the concept of longshore drift.
      ::创建一个图表来说明长岸漂移的概念。

    Think Critically
    ::仔细仔细思考

    1. Why are the smallest particles on a beach usually sand?
      ::为什么沙滩上最微小的粒子 通常都是沙子?
    1. Explain how a barrier island helps protect the coast from wave erosion.
      ::解释一个屏障岛如何帮助保护海岸免受波浪侵蚀。
    1. Compare and contrast how breakwaters and groins protect shorelines.
      ::对比和对比 防波堤和腹股沟如何 保护海岸线。

    Points to Consider
    ::需要考虑的要点

    Moving air, like moving water, causes erosion. Moving air is called wind.
    ::移动空气,像移动水一样, 造成侵蚀。 移动空气被称为风。

    • How does wind cause erosion? Does the wind carry particles in the same ways that moving water does?
      ::风能如何造成侵蚀?风能以移动水的同样方式携带粒子吗?
    • What landforms are deposited by the wind?
      ::风所沉积的地表是什么?