1. Ocean Pollution

2. What is pollution? Pollution occurs when an environment is contaminated, or dirtied, by waste, chemicals, trash, and other harmful substances. The world’s oceans are facing many threats due to pollution.

3. Sources of Water Pollution Water pollution is the contamination of bodies of water such as lakes, rivers, oceans, and groundwater, often by human activities. Sometimes, water pollution can occur through natural causes like algae blooms, animal waste, volcanic eruptions, and floods. However, a lot of water pollution is the result of humans, such as sewage, pesticides, fertilizers, and trash.

4. Sources of Water Pollution Water pollution can originate from a number of sources. If the pollution comes from a single source, such as an oil spill, it is called point-source pollution. If the pollution comes from more than one source, such as toxic chemicals from runoff, it is called non- point source pollution.

5. Sources of Water Pollution Most types of pollution affect the immediate area surrounding the source. But sometimes the pollution may affect an environment hundreds of miles away such as nuclear waste. This is called trans-boundary pollution.

6. Types of Water Pollution 1.Surface Water Pollution – Surface water is the natural water found on Earth’s surface such as rivers, lakes, lagoons, and oceans. When hazardous substances come directly into contact with surface water, it mixes or dissolves. This is called surface water pollution. 2.Nutrients Pollution – Some wastewater, fertilizers, and sewage contain high levels of nutrients. After getting washed away by rain, they end up in large bodies of water. The extra nutrients cause algae to grow. This makes the water undrinkable and unsafe for animals to live in. This is because the excess algae use up all the oxygen in the water.

7. Types of Water Pollution 3.Oxygen Depleting Pollution – Any body of water is home to microorganisms, both aerobic (requires oxygen) and anaerobic (do not require oxygen). When too much biodegradable matter ends up in the water, it allows these microorganisms to thrive. Just like algae, they end up depleting the oxygen in the water. Eventually, the aerobic organisms die due to the lack of oxygen. In turn, the anaerobic continue to thrive, producing harmful wastes such as ammonia and sulfides.

8. Types of Water Pollution 4.Groundwater Pollution – The pesticides and chemicals used in agriculture are eventually washed from the soil or pushed deep into the ground by rainwater. Water found deep underground collects these harmful chemicals in high concentrations. This means when we dig wells for drinking water, the water needs to be checked for harmful water pollution.

9. Types of Water Pollution 5.Microbiological Pollution – Not everyone around the world has access to clean drinking water. In America, our drinking water is filtered and treated to remove natural pollution caused by microorganisms like bacteria and viruses. In excess, this type of pollution (though natural) can cause animals who live in the water to get sick and die. It can also cause serious illnesses to humans who drink that water.

10. Types of Water Pollution 6.Suspended Matter Pollution – Not all substances dissolve easily into water. These substances are called particulate matter and are suspended in the water column. Eventually, the suspended particulate matter settles to the bottom of the body of water. If the matter is toxic and harmful, it can harm and kill aquatic life. 7.Chemical Pollution – Many industries, including agriculture, use chemicals on the land that eventually end up in our oceans. These chemicals are usually poisonous to aquatic life. The United States government has issued laws to regulate how companies dispose of harmful chemicals in order to protect the environment. However, it is often difficult to enforce these laws.

11. Impacts of Pollution on Marine Wildlife The main (and most obvious) impact of water pollution on marine wildlife is that pollution causes illness and death to organisms that depend on that body of water. This can be direct or indirect depending on the type of pollution. For example, a plastic garbage bag will directly harm a sea turtle if it mistakes the bag for a jelly fish and swallows it. Animals are indirectly affected by water pollution by the transfer of harmful pollutants through several chemical and biological processes.

12. Impacts of Pollution on Marine Wildlife Bioaccumulation explains how chemicals and other toxins enter the food chain and become more concentrated as they are passed from animal to animal.

13. Impacts of Pollution on Marine Wildlife The nitrogen cycle is the process by which atmospheric nitrogen is converted into various forms so organisms can use it to produce amino acids and proteins. The steps of the nitrogen cycle include: 1.Nitrogen Fixation – Most fixation is completed by specialized bacteria living in soil who consume atmospheric nitrogen and use it to produce ammonia. 2.Nitrification – The same bacteria then converts the ammonia into other organic compounds, such as nitrates.

14. Impacts of Pollution on Marine Wildlife 3.Assimilation – Plants can now absorb the nitrates from the soil into their roots. The nitrates are used to produce amino acids and proteins. Nitrates are passed up the food chain as herbivores consume plants and carnivores consume herbivores. 4.Denitrification – Bacteria use nitrogen from animal waste for respiration. The result is nitrogen gas that re-enters the atmosphere. The nitrogen cycle then re-starts from here. 5.Ammonification – When a plant or animal dies, decomposing organisms, such as fungi and bacteria, convert the nitrogen back to ammonia so it can also re- enter the nitrogen cycle.

15. Impacts of Pollution on Marine Wildlife

16. Excess amounts of nitrogen in the ocean can result in a large algal bloom which ultimately depletes oxygen levels in the water.

17. Impacts of Pollution on Marine Wildlife In a process called eutrophication, nutrients (nitrogen) enrich the water allowing the algae to grow. If there is an excessive amount of nutrients, the algae can grow more rapidly than animals can consume them. The algae eventually die and begin to decompose – a process that consumes oxygen and produces carbon dioxide. The water eventually becomes devoid of oxygen causing animals to die or leave the area. This oxygen depleted area is called a hypoxic area or dead zone.

18. Impacts of Pollution on Marine Wildlife Approximately 80% of trash in the oceans comes from human activities. And an estimated 1.4 billion pounds of trash in dumped into the ocean every year! Wind and ocean currents carry this trash into the center of gyres, which are giant circular oceanic surface currents.

19. Preventing Pollution Preventing ocean pollution is something that everyone including governments, researchers, educators, and students should be involved with. There are many things even you can do to help! −Learning about the issue and sharing your knowledge is the greatest and most important thing you can do.

20. Questions?