2.5 Impact of Oil Pollution

2026 📋 Syllabus Objectives

By the end of this topic, you should be able to:

  1. Describe the causes of oil pollution in marine and coastal ecosystems.
  2. Describe the impacts of oil pollution on birds, marine mammals, coral reefs, and beaches.

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What Is Oil Pollution?

Oil pollution happens when crude oil (the thick, dark liquid pumped from underground) or refined oil products enter the sea or coastal areas. Oil does not mix with water — it spreads across the surface in a thin layer called an oil slick. This slick can travel long distances, carried by waves and ocean currents, spreading damage far from where the spill first happened.

Causes of Oil Pollution

The syllabus identifies three main causes. You need to know all three.

1. Offshore Oil Extraction

  • Offshore means "out at sea." Oil companies build large structures called oil rigs or offshore platforms in the ocean to drill down through the seabed and pump oil up.
  • Accidents can happen during drilling. If equipment fails or there is an explosion, large amounts of oil can gush out of the well directly into the sea. This is called a blowout.
  • Even during normal operations, small leaks and spills can occur, releasing oil into the surrounding ocean over time.
  • Because rigs are far from shore, these spills are difficult to respond to quickly, allowing the oil to spread widely before help arrives.

2. Pipelines

  • Once oil is extracted, it must be transported. One method is to pump it through long pipelines — metal tubes that carry oil under the sea or across land to refineries and ports.
  • Pipelines can corrode (rust and weaken) over time, or they can be damaged by storms, earthquakes, or human error.
  • When a pipeline cracks or bursts, oil leaks out continuously until the break is fixed. Because some pipelines run along the ocean floor, these leaks are hard to detect and even harder to repair, meaning large volumes of oil can escape before the problem is noticed.

3. Shipping

  • Huge vessels called oil tankers carry millions of litres of crude oil across oceans. If a tanker crashes into rocks, runs aground (gets stuck on the seabed in shallow water), or collides with another ship, its hull (the outer shell) can split open.
  • This releases enormous quantities of oil into the sea very quickly — sometimes hundreds of thousands of tonnes at once.
  • Routine shipping activities also cause pollution on a smaller scale. For example, some ships illegally flush their tanks with seawater and dump the oily mixture into the sea.
  • Fuel oil can also leak from a ship's engine during normal operation.

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