Does the presence of nitrates affect water quality?
Unlike temperature and dissolved oxygen,
the presence of nitrates usually does not have a direct effect on aquatic
insects or fish. However, excess levels of nitrates in water
can create conditions that make it difficult for aquatic insects or
fish to survive.
Algae and other plants use nitrates as a
source of food. If algae have an unlimited source of nitrates,
their growth is unchecked. So, why is that a problem?
Which river is most likely affected by high levels of nitrates?
The river on the right is as green as pea soup,
a result of high concentrations of algae. Click here
to see other examples of how nitrate levels affect algae growth in
Large amounts of algae can cause extreme
fluctuations in dissolved oxygen. Photosynthesis by algae
and other plants can generate oxygen during the day. However, at night, dissolved oxygen may decrease to very low levels as a
result of large numbers of oxygen consuming bacteria feeding on dead
or decaying algae and other plants.
the presence of nitrates affect human health?
People who use wells as a source of drinking water
need to monitor the level of nitrates in their well water. If you drink water that is high in nitrates, it
can interfere with the ability of your red blood cells to
transport oxygen. Infants who drink water high in nitrates may
turn "bluish" and appear to have difficulty in breathing
since their bodies are not receiving enough oxygen.
Just like dissolved oxygen, temperature, and pH,
the amount of nitrates in water is determined by both natural processes and
human intervention. A body of water may be naturally high
in nitrates or have elevated nitrate levels as a result of careless human
In this unit, you will be introduced to the
concept of nitrates and how nitrates can influence the aquatic
environment. The relationship between nitrate and dissolved
oxygen levels will be introduced.
This unit will also discuss how nitrate levels are influenced by nature
as well as man-made processes.
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