2.3 Waves, tides, and coastal processes

Ocean waves and tides shape our coasts and seas. Wind creates waves, while the moon and sun cause tides. These forces constantly move water, affecting everything from tiny organisms to massive shorelines.

Coastal processes like erosion and deposition sculpt beaches and cliffs. These dynamics impact marine life and human activities, influencing where we build, swim, and sail. Understanding these patterns helps us protect and enjoy our coasts.

Ocean Waves

Characteristics of ocean waves

Top images from around the web for Characteristics of ocean waves

• 

  17.1 Waves | Physical Geology View original

  Is this image relevant?

• 

  Biogeography | OpenStax Biology 2e View original

  Is this image relevant?

• 

  10.1 Wave Basics – Introduction to Oceanography View original

  Is this image relevant?

• 

  17.1 Waves | Physical Geology View original

  Is this image relevant?

• 

  Biogeography | OpenStax Biology 2e View original

  Is this image relevant?

1 of 3

Top images from around the web for Characteristics of ocean waves

• 

  17.1 Waves | Physical Geology View original

  Is this image relevant?

• 

  Biogeography | OpenStax Biology 2e View original

  Is this image relevant?

• 

  10.1 Wave Basics – Introduction to Oceanography View original

  Is this image relevant?

• 

  17.1 Waves | Physical Geology View original

  Is this image relevant?

• 

  Biogeography | OpenStax Biology 2e View original

  Is this image relevant?

1 of 3

• Formation of ocean waves
  • Wind blows over water surface transferring energy from wind to water creating waves
  • Factors affecting wave characteristics include wind speed, duration, and fetch (distance wind blows over water)
• Wave height measures vertical distance between wave crest and trough
• Wave period measures time for two consecutive wave crests to pass a fixed point
• Wavelength measures horizontal distance between two consecutive wave crests or troughs
• Water depth and ocean floor topography also influence wave characteristics

Tides and Coastal Processes

Causes and effects of tides

• Gravitational pull of moon and sun on Earth's oceans causes tides
  • Moon's influence stronger due to proximity to Earth
• Spring tides occur during new and full moons when sun, moon, and Earth align
  • Result in higher high tides and lower low tides
• Neap tides occur during first and third quarter moons when sun and moon are perpendicular
  • Result in lower high tides and higher low tides
• Tides cause intertidal zones to experience cyclical exposure and submersion
• Tidal currents influence water circulation and nutrient distribution in coastal areas

Processes in coastal environments

• Erosion involves removal and transport of sediment by waves, currents, and wind
  • Hydraulic action: force of waves hitting shoreline
  • Abrasion: sediment carried by waves scraping against shoreline
  • Attrition: collision of sediment particles reducing their size
• Deposition involves accumulation of sediment transported by waves and currents
  • Occurs when wave energy decreases allowing sediment to settle
  • Leads to formation of coastal features (beaches, spits, barrier islands)
• Longshore drift transports sediment along shoreline by waves approaching at an angle
  • Results in gradual movement of sediment and reshaping of coastline

Impact of coastal dynamics

• Marine ecosystems
  • Intertidal zones support diverse communities adapted to cyclical exposure and submersion
  • Coastal erosion and deposition create and modify habitats (rocky shores, sandy beaches)
  • Tidal currents influence nutrient distribution and larval dispersal
• Human activities
  • Coastal development and infrastructure vulnerable to erosion and flooding
  • Navigation and shipping affected by tides and tidal currents
  • Recreational activities (surfing, beach-going) depend on wave conditions
  • Coastal management strategies (beach nourishment, seawall construction) aim to mitigate effects of erosion and protect coastal communities