Act! Join Us Support Our Efforts
Ocean Conservation Marine Life Species Database Education+Careers Projects Contributors Photos Videos News Connect

Ocean Pollution

Marine Conservation Home / NEXT: Ocean Resources »

The Effects of Runoff and Pollution

The ocean is the basin that catches almost all the water in the world. Eventually, water evaporates from the ocean, leaves the salt behind, and becomes rainfall over land. Water from melted snow ends up in rivers, which flows through estuaries and meets up with saltwater. Fertilizers, pesticides, and oil, mostly from farms, seep into the ground after a rain and then stream into rivers and ultimately into the ocean. Feedlots in the United States exceed the amount of human waste with more than 500 millions tons of manure each year.

Not only does the waste flow into the ocean, but it also encourages algal blooms to clog up the waterways, causing meadows of seagrass, kelp beds and entire ecosystems to die. A zone without any life remaining is referred to as a dead zone and can be the size of entire states, like in coastal zones of Texas and Louisiana. All major bays and estuaries now contain dead zones from pollution run-off and in 2008, 405 dead zones were counted worldwide. Pollutants like mercury (2), DDT, PCBs and pesticides are becoming more commmon in seafood meant for the dinner table and cause birth defects, cancer and neurological problems—especially in infants.


Water recreation is another aspect of human life compromised by marine pollution from human activities like roads, shopping areas, and development in general.

Swimming is becoming unsafe, in 2008, of the 3,740 coastal beaches that were monitored, 1,210 had at least one advisory or closure due to contamination from pollutants. Developed areas like parking lots enable runoff to occur at a much higher volume than a naturally absorbent field. Even simply driving a car or making a house warm can leak 28 million gallons of oil into lakes, streams and rivers.

Environmental Laws

In addition to the lack of underwater national parks, there is no universal law like the Clean Air Act or the Clean Water Act to protect the United States ocean territory. Instead, there are many different laws like the Magnuson-Stevens Fishery Conservation and Management Act, which only apply to certain aspects of overfishing and are relatively ineffective. The act developed in the 1970's is not based on scientific findings and is regulated instead by the regional fisheries council. In 2000, the Oceans Act was implemented as a way to create a policy similar to the nationwide laws protecting natural resources on land. However, this act still needs further development and, like many of the conservation laws that exist at this time, it needs to be enforced.


A major factor in the destruction of habitats is the development of coasts and the loss of water quality.

Usually, coastal marshes can help control pollution by filtering out normal pollutants and providing a safe haven for young fish and other wildlife. However, these marshes are vanishing at 20,000 acres a year and most of the seagrass cover is being lost very quickly in places like Tampa Bay and the Mississippi Sound.

Another crucial ecosystem is the coral reef, a place of great biodiversity, recreational value, a sanctuary for most young fish and very important to the protection of coastlines during storms. Unlike terrestrial national parks that are in full view, pristine underwater areas are rarely seen by the United States government as high priority.

The Ocean Ecosystem

The ocean is a complex and interwoven ecosystem with each biotic and abiotic factor influencing every other component directly or indirectly. When one habitat vanishes, organisms that rely on that niche can no longer survive.

Animals like sea turtles, manatees, fish, shrimps and crabs rely on seagrass for survival. Unfortunately, seagrass is sensitive to dredging of channels, pollution and development and is being lost at an alarming rate. Since the ocean is an interlaced ecosystem, the loss of one species like sea otters can cause sea urchins (their prey) to soar in numbers. The loss of biodiversity in the oceans is more critical than simply losing a source of wonder for future generations. Loss of biodiversity has the power to affect human survival in the future in a profound way. For example, species like sea sponges have been found to hold chemicals capable of beating cancer and viruses, but they will be lost if pollution from runoff and ocean dumping is not curbed dramatically.

~^~ surface

Feedback & Citation

Start or join a discussion below about this page or send us an email to report any errors or submit suggestions for this page. We greatly appreciate all feedback!

~^~ surface

Help Protect and Restore Ocean Life

Help us protect and restore marine life by supporting our various online community-centered marine conservation projects that are effectively sharing the wonders of the ocean with millions each year around the world, raising a balanced awareness of the increasingly troubling and often very complex marine conservation issues that affect marine life and ourselves directly, providing support to marine conservation groups on the frontlines that are making real differences today, and the scientists, teachers and students involved in the marine life sciences.

Join us today or show your support with a monthly donation.

With your support, most marine life and their ocean habitats can be protected, if not restored to their former natural levels of biodiversity. We sincerely thank our thousands of members, donors and sponsors, who have decided to get involved and support the MarineBio Conservation Society.