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Human Impact on Oceans — Reading Comprehension

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MS-ESS3-3
MS-ESS3-4

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This comprehensive middle school science passage examines the multiple threats human actions pose to the world’s oceans, including overfishing, pollution, ocean acidification, warming, and habitat destruction. Students will learn how these processes work, the mechanisms behind each threat, and their effects on marine life and ecosystems. The text integrates scientific thinking, cause-and-effect chains, and real-world data, and also highlights possible solutions such as marine protected areas and sustainable fishing. Aligned with NGSS standards MS-ESS3-3 and MS-ESS3-4, the resource supports reading comprehension, vocabulary development, and critical thinking. Activities include multiple-choice questions, writing prompts, and graphic organizers. The resource also features an audio option to support diverse learners. This engaging, standards-based curriculum tool is ideal for grades 6-8 science classrooms exploring environmental systems and conservation.

CONTENT PREVIEW

ocean-acidification-3 — Effects of acidification on marine organisms

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?

It removes fish faster than they can reproduce.It pollutes the water with chemicals.It lowers the temperature of the water.It increases the number of predators.

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

Great Pacific Garbage PatchCoral bleachingRising sea levelsOcean acidification

What is bycatch?

Catching fish that are too small to eatCatching unintended species like turtles or dolphinsPlanting coral reefsCleaning up plastic from the ocean

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

Agricultural runoff and oil spillsCoral bleachingMarine protected areasOverfishing

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

Fishing areas where fish populations are too low to continue fishingOceans polluted with chemicalsAreas of ocean protected from fishingPlaces where coral reefs have died

What is ocean acidification and why is it a problem?

The ocean becomes more acidic from absorbing CO₂, making it hard for shell-forming organisms to survive.The ocean becomes warmer due to sun exposure.Plastic dissolves in the ocean, harming fish.The ocean gets saltier and causes fish to leave.

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

Establishing marine protected areas.Building more coastal developments.Increasing fishing quotas.Using more plastic products.

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

They may struggle to build their skeletons and die.They will grow faster.They will attract more fish.They will become more colorful.

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

TrueFalse

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

TrueFalse