Oceanography and Geological Phenomena Notes

Tides

• Spring Tide

  • Occurs when the Earth, Moon, and Sun are aligned.

  • Results in higher high tides and lower low tides.

• Neap Tide

  • Occurs when the Moon is at a right angle to the Earth and Sun.

  • Results in lower high tides and higher low tides.

El Niño

• Overview

  • Phenomenon characterized by unusually warm ocean temperatures in the equatorial Pacific.

• Impacts

  • Weakens trade winds, which typically blow from east to west.

  • Leads to:

  • Prevention of upwelling off the coast of Peru, leading to lower productivity in marine life.

  • Drought conditions in Indonesia and Australia.

  • Increase in storms along the South American coast.

La Niña

• Overview

  • Opposite of El Niño, characterized by cooler ocean temperatures in the equatorial Pacific.

• Impacts

  • Stronger trade winds lead to higher upwelling, resulting in:

  • Higher marine productivity.

  • Larger food web due to increased nutrient availability.

  • Increased storms in the Indo-Australian region.

Ocean Currents

• Surface Currents

  • Driven by wind, tides, and the Coriolis effect.

• Deep Currents

  • Driven by thermohaline circulation (temperature and salinity).

• Upwelling

  • Movement of deep, cold, nutrient-rich water to the surface.

  • Caused by strong winds blowing coastal water offshore, allowing cold water to rise.

• Downwelling

  • Movement of oxygen-rich surface waters to the deep sea, density-driven.

Geological Activity

• Earthquakes

  • Occur at convergent and transform boundaries where tectonic plates may become stuck.

  • When the pressure builds and is suddenly released, seismic waves are generated.

• Volcanic Activity

  • Occurs where pressure builds due to gas/magma, which can escape through volcanoes, forming new landforms over time.

  • Magma buildup contributes to eruptions, releasing gases and ash into the atmosphere.