Human Impact on Oceans — Reading Comprehension

Oceans cover more than 70% of Earth’s surface and play a critical role in supporting life, regulating climate, and providing food and resources. In recent decades, scientists have observed dramatic changes in marine environments caused by human activities. Understanding human impact on the oceans is vital because the health of the oceans affects ecosystems, economies, and people worldwide. This passage examines how overfishing, pollution, climate change, and habitat destruction threaten marine life and what can be done to protect our oceans.

Mechanisms of Human Impact

Overfishing occurs when people catch fish faster than populations can reproduce. This depletes fish stocks and has led to collapsed fisheries, where once-abundant species are now rare or even extinct in some regions. Bycatch—catching unintended species like turtles and dolphins—also harms marine biodiversity. Pollution is another major threat. Plastic pollution, such as the Great Pacific Garbage Patch, introduces millions of tons of plastic into the ocean each year. Microplastics, tiny plastic fragments, can enter the food chain and harm animals. Oil spills and agricultural runoff cause ‘dead zones’ with little oxygen, making it impossible for most marine life to survive. Chemical contamination can poison food webs and disrupt reproductive cycles.

Climate Change and Ocean Health

Oceans absorb about 30% of human-produced carbon dioxide (CO₂), which lowers the pH of seawater—a process called ocean acidification. Acidification interferes with the ability of shell-forming organisms, like corals and mollusks, to build their skeletons. Coral reefs, which support 25% of marine species, are especially vulnerable. Warming oceans lead to coral bleaching, where stressed corals lose their color and may die. Rising sea levels and shifting species ranges add to the challenges faced by marine ecosystems.

Habitat Destruction and Solutions

Human development along coasts, destructive fishing practices like bottom trawling, and damage to coral reefs destroy essential marine habitats. These actions break important links in the ocean food web and reduce biodiversity. However, solutions exist. Establishing marine protected areas, enforcing sustainable fishing practices, reducing plastic use, and taking climate action can help restore ocean health. Conservation efforts depend on scientific research, global cooperation, and public awareness.

Protecting the oceans is not just an environmental issue—it is necessary for the survival of countless species, human food security, and Earth’s natural systems.

Interesting Fact:
Every minute, the equivalent of one garbage truck of plastic enters the ocean.

What is the main reason overfishing is harmful to the ocean?

Which of the following is a major source of plastic pollution in the ocean?

What is bycatch?

According to the passage, what causes dead zones in the ocean?

What does the word 'collapsed fisheries' mean as used in the passage?

What is ocean acidification and why is it a problem?

Which solution is suggested in the passage to help protect the ocean?

If ocean acidification continues, what might happen to coral reefs?

True or False: Marine protected areas are ocean zones where fishing is encouraged.

True or False: Climate change and pollution are both threats to ocean health.