other factors that affect the amount of dissolved oxygen?
material comes from parts of trees and plants that fall into a body
of water. Organic material also includes decaying algae, dead
aquatic plants, dead fish or other organisms, and human and animal
wastes. Organic material does not directly remove the DO,
but it creates conditions where large amounts of bacteria accumulate.
These bacteria consume large amounts of DO, driving the overall
oxygen level down.
and Phosphates. If you've ever spread fertilizer
on a lawn, you'd probably know that nitrates and phosphates are
the main component. When these chemicals are in high concentrations
in water, they do the same thing. They fertilize. This
causes algae and aquatic plants to thrive. As a result, two
1. A rate
of plant growth occurs that cannot be sustained. Plants
grow so dense that eventually they choke each other off.
Large amounts of plant material accumulates, creating organic
matter and large amounts of oxygen-demanding bacteria.
grow and create an unstable DO level. A large algae
population will create oxygen during the day (photosynthesis),
but only consumes it during the night (no light for photosynthesis).
This results in a very low DO level just before sunrise, creating
stressful conditions for some aquatic organisms.
| Objectives | Pre-Test
| Presentation | Activity
Quality Modules |
Pages | Standards