Ocean Currents and Shoreline Features

Thermohaline Circulation

• Driven by variations in water density, influenced by temperature (thermo) and salinity (haline)
• Warm, less salty surface water flows towards the poles
• Water cools and becomes saltier, increasing density, leading to sinking
• Cold, dense water flows along the ocean floor towards the equator
• This deep flow eventually upwells, bringing nutrients and contributing to surface current patterns

Global Water Movements

• Surface currents driven by wind patterns
• Deep ocean currents driven by density differences
• These combined currents form a global network of circulating water
• Surface currents transport heat, influencing regional climates
• Deep currents play a crucial role in nutrient distribution and oxygenation

Shoreline Features

Wave Erosion

• Wave-cut platform: a flat, rocky surface created by wave erosion at the base of a cliff
• Cliffs: steep, vertical rock faces formed by wave erosion
• Terraces: step-like platforms created by wave erosion and uplift
• Sea arches: natural archways formed by wave erosion through headlands
• Sea stacks: isolated rock formations left behind after wave erosion of headlands

Sediment Deposition

• Spits: narrow sand deposits extending from the coastline
• Bars: submerged or exposed sand deposits parallel to the coast
• Tombolos: sand deposits connecting an island to the mainland
• Barrier Islands: long, narrow islands separated from the mainland by lagoons

Wave Structure

• Crest: highest point of a wave
• Trough: lowest point of a wave
• Wavelength: distance between two successive crests or troughs
• Wave height: vertical distance between the crest and trough
• Wave period: time it takes for one complete wave cycle to pass a given point

Wave Interaction with the Seafloor

• Wave "feels bottom" when depth is less than half the wavelength
• Wave breaks when the depth is about 1.3 times the wave height

Tides

• Regular rise and fall of sea level caused by gravitational pull of the Moon and Sun
• Moon's gravitational pull is stronger than the Sun's due to its proximity to Earth

Spring Tides

• Earth, Moon, and Sun aligned (new moon or full moon)
• Strongest gravitational pull
• Highest high tides and lowest low tides

Neap Tides

• Earth, Moon, and Sun at 90° angles (first or third quarter moon)
• Weaker gravitational pull
• Lower high tides and higher low tides

Tidal Patterns

• Diurnal: One high and one low tide each day
• Semidiurnal: Two high and two low tides each day
• Mixed: Two high tides and two low tides each day, with unequal heights