When you think of the ocean, what do you picture? Do you imagine sparkling blue waters and shimmering schools of fish? Or do you think of immense patches of plastic waste drifting across an area twice the size of the continental United States? Both of these pictures are the truth. Marine pollution poses a serious threat to marine life and habitats, and even to humans. However, people are tackling the problem with efforts at cleanup and, more importantly, prevention.

Causes and Types of Marine Pollution

Marine pollution comes from many sources, such as oil and chemicals that are spilled in accidents at sea. In addition, rain washes fertilizers from fields into rivers and streams that feed into the ocean, and sewage drains into waterways. Finally, wind and natural disasters scatter trash into the ocean.

This last type of litter is often referred to as marine debris, and it is one of the greatest threats to marine ecosystems. Once marine debris reaches the ocean, it is picked up and carried along by currents. Currents are the movement of the water in a particular direction, driven by tides or wind.

The most common type of marine debris is plastic. This is because humans make and use a lot of it, and because plastic can float. Additionally, many kinds of plastic do not biodegrade, or naturally break down, in water. Instead, they fall apart into microplastics, pieces that are too small to see easily. They are then carried along with the currents, like all of the other marine debris.

Garbage Patches

In some parts of the ocean, currents form large, rotating systems called gyres. Debris becomes trapped and begins to accumulate. This is especially true in the Pacific Ocean, where the currents have created what some people call the Great Pacific Garbage Patch. In this area, scientists have found as many as 1.9 million pieces of debris in a square mile.

Some experts think the term “garbage patch” is inaccurate because it implies that the trash forms an island. Instead, these “patches” are regions with high levels of very small pieces of debris. They are constantly moving and cannot be seen by satellites. Therefore, it is hard to tell exactly how large these regions are.


Wind and wave patterns cause tiny plastic debris to concentrate in huge areas sometimes called “garbage patches."
Effects of Marine Pollution


Larger pieces of marine debris also have significant negative effects on the ocean environment. Fish, birds, and turtles become tangled in plastic bags. Also, fishing boats leave behind traps, nets, and lines that can catch fish and other animals.

Cleaning Up the Seas

Finding a solution to the marine debris problem has been a challenge. The debris is hard to see and hard to track. Scooping it off the ocean surface is difficult for many reasons. First of all, the process is time-consuming because the polluted areas are so large. Also, when trash is skimmed off the surface, microscopic sea creatures become trapped with the debris. Furthermore, larger items that sink to the bottom are out of reach.

However, prevention can help. Dianne Sherman of the International Coastal Cleanup estimates that “50 to 80 percent of what ends up in the ocean starts out on land.” As a result, many organizations focus on cleaning up the debris before it reaches the water. This includes removing trash from beaches and cleaning up after natural disasters such as hurricanes.

Marine pollution has already affected countless species. This much is clear: doing nothing is not an option. Despite the size of the problem, we can all help. We must stop littering. We must support the organizations that study marine pollution. And finally, we must work to decrease the amount of waste we produce. These efforts may not undo the damage that has been done, but they could bring a future of cleaner waters.

What is the thesis, or central idea, of this article? How does it influence the author’s choice of organizational strategy?

A
“Marine pollution comes from many sources”; this thesis calls for comparing and contrasting the different forms of pollution.

B
“Finding a solution to the problem of pollution is a challenge”; this thesis calls for comparing and contrasting different cleanup methods to figure out the best one.

C
“Marine pollution poses a serious threat to marine life and habitats and even to humans”; this thesis calls for a discussion of a cause, marine pollution, and its effects, threats to animals and humans.

D
“People are tackling the problem with efforts at cleanup and, more importantly, prevention”; this thesis calls for a discussion of a cause, cleanup efforts, and the effects, preventing further pollution.