Chapter 15 Water Pollution

What is the difference between oligotrophic and eutrophic?

-Oligotrophic means relatively low in plant nutrients (clear water) and containing high amounts dissolved oxygen in the deeper parts.

-Eutrophic means relatively high in plant nutrients/algae and containing low amounts of dissolved oxygen in the deeper parts

What is meant by hypoxic?

-Hypoxic is a condition in which a body of water contains inadequate levels of oxygen, compromising the health of many aquatic organisms.

-Less oxygen is produced as algae take over the role of photosynthesis from the submerged aquatic plants. With less oxygen in the water, other organisms begin to die and decompose. Decomposition uses up more of the limited oxygen leaving the system hypoxic

Why is the hypoxic zone so large at the mouth of the Mississippi River?

-Excess nitrogen and phosphorous delivered by the Mississippi River provides an explanation for the development of the hypoxic zone in the Gulf of Mexico.

-Lack of wetlands.

What causes human-induced eutrophication?

-Uncovered manholes allow chemicals from city streets to enter the storm drains.

-Water from storm drains, as well as agricultural and suburban runoff, end up flowing into rivers, streams, lakes, and seas.

-The nitrogen and phosphorus contained in fertilizers that, when washed into a waterway, provide a boost to plant and algae growth.

-Runoff pollution from roadways, urban areas and industries throughout the watershed, fertilizer and pesticide runoff animal water from pasture and agricultural land.

What is the process of human-induced eutrophication and hypoxia?

1. For many plants and algae nitrogen and phosphorus are limiting nutrients. These are contained in fertilizers that, when washed into a waterway, provide a boost to plant and algae growth.

2. As the algae flourish, light penetration is reduced and submerged aquatic plants can no longer photosynthesize.

3. As plants and other organisms die, decomposers use up what little oxygen remains.

Why does eutrophication cause hypoxic zones? That is, why does oxygen content decrease below levels needed for all the life forms requiring oxygen to respire?

-Less oxygen is produced as algae take over the role of photosynthesis from the submerged aquatic plants.

-With less oxygen in the water, other organisms begin to die and decompose.

-Decomposition uses up more of the limited oxygen, leaving the system hypoxic

-The lack of oxygen in the water cause less plants and animals in the water

What is point source vs. non-point source pollution?

-Point Source: any single identifiable source of pollution from which pollutants are discharged, such as a pipe or factory smokestack

-Non-Point Source: comes from a variety of sources and its runoff during rainfall enters the water

How do impervious surfaces contribute to water pollution in cities and suburbs?

Stormwater that doesn't soak into the ground can enter storm drains that flow directly to lakes and rivers, or cause floods, especially in heavily built-up urban settings.

What are a few examples of point source and non-point source water pollution?

-Point Source: Sewage treatment plant overflow, animal feedlot, industrial waste discharge

-Non-Point Source: open mines, cropland animal pasture, construction sites

Where does stormwater runoff go? Does it go through water treatment plant, like the one you visited?

Stormwater that doesn't soak into the ground can enter storm drains that flow directly to lakes and rivers, or cause floods, especially in heavily built-up urban settings.

What role can marsh plants play in decreasing the rate of eutrophication? Think about what you learned at the JBS Wetlands Center.

-A marsh have many indigenous species of grass that require less fertilizer and water.

Planting water-tolerant plants -in low areas also helps by reducing runoff.

-Marshes act as natural filters for runoff which improve the water quality.

What is a watershed?

A watershed is an area or ridge of land that separates waters flowing to different rivers, basins, or seas.

What is the problem with Nitrogen runoff?

Excess nitrogen from any rivers and streams within the watershed will eventually flow to a larger body of water. The nitrogen when washed into a waterway, provide a boost to plant and algae growth.