Aquatic
invertebrates
Aquatic invertebrates are tiny organisms such
as insects or crustaceans, that live in creeks, rivers, and other waterways.
Because of their small size, they are hardly ever noticed,
but they serve an important role in the ecology of waterways. These invertebrates
are the primary consumers in an aquatic ecosystem, feeding on algae and
other plants which are the producers in the food pyramid.
Secondary consumers, such as fish, feed on the primary consumers. Tertiary
consumers, such as birds or mammals, then prey on the secondary consumers.
Disruption
of the food pyramid by pesticides
Many people do not realize the impact that
pesticides have on fish and other organisms in our creeks and rivers.
Residue from a pesticide application may be washed into storm drains
during irrigation or rain. In many cities, the stormwater leads directly
into our creeks and rivers.
Diazinon, chloryprifos, and pyrethroids have
been identified as imparing water quality because they occur at levels
toxic to Ceriodaphnia and Hyalella, tiny
aquatic animals which are representative of the many invertebrates in
water. This sets off a chain reaction and disrupts the food pyramid.
When these organisms die, secondary consumers like fish starve or must
look for a new location to reside. The lack of secondary consumers then
affects the tertiary consumers, causing them to starve or forcing them
to move to new locations.
|
>> Move
your cursor over the illustration to see how a disruption to aquatic
invertebrates, such as Ceriodaphnia, would affect the entire
food pyramid.
Illustrations
by Celeste Rusconi. |
