Geology Home Page
Roger Weller, geology instructor
by Sean Harvey
Many creatures help revitalize the earth, some through balancing the
topsoil of our plant by enriching it with nutrients and air flow. The mighty
earthworm is our discussion point today. The earthworm is efficient at creating
and maintaining soil that, through growth of food products, can sustain the
whole plant. This industrious creature, by successfully accomplishing its day to
day activities allows the circle of life to continue to flourish.
The earthworm family includes approximately 2,700 different species.
All 2,700 varieties offer the same benefits to our earth through maintaining
and stabilizing our topsoil. The most common earthworm found in North
America is the Nightcrawler or Lumbricus Terristris. This busy little earthworm
helps the first and second layer of the topsoil. The three most important items
the earthworm does for our topsoil are:
The earthworm secretes nitrogen.
While the earthworm is moving through the soil, it mixes the
secretion with the A Horizon and B Horizon. This compost,
when completely mixed, creates a more balanced mineral
Again, through the movement in the topsoil, the earthworm
is aerating the soil, and as a byproduct, aerating the soil after
a good solid rainstorm
Topsoil is essential to plant growth. Making worms a key component
for the creation of good topsoil. The Earthworm came to North America
by European colonials in simple gardening plants. This was one of the
few introductions of a foreign species to have its advantages out weight
The Earthworm utilizes its physical structure to help propagate the
decomposition of debris. By having a slim-line body it can borrow itself
deep into the earth, about 6 feet, and not burn much energy. The
worm when borrowing into the earth does not purposely make top
soil rich in nitrogen, but it’s a bi-product of the worm decomposing
matter. When a worm ‘eats’ the soil in the earth is broken down into
the nutrients it needs and secretes the minerals it does not need.
One of these minerals it secrets is nitrogen. Nitrogen is very important
to plants and other carbon based life forms. This nitrogen is taken into
the roots and the plants turn into lush green life. Nitrogen from the
plants can be then transformed into the nutrients the plant needs.
This plant now is rich in nitrogen and can be consumed by any herbivore
or omnivorous creature that eats it. The worms also leave other trace
minerals to help give
the topsoil enriched minerals.
Worms travel deep into the earth and have been known to average
about six feet into the soil. This crosses the A horizon layer and B
horizon layer found within the ground. When the worm crosses the
A horizon and B horizon the ground mixes its soil and mixes the
minerals within the ground together within the two horizons. This
creates a more balanced composition within the ground and helps
plants’ roots group deeper for the same nutrients. This allows the
plants roots to grow in a uniform fashion deep within the topsoil
without little interference from the ground lacking sufficient minerals.
With the two inner mixing horizons the effective topsoil is deeper and
allows for plants to become enriched with minerals wherever their roots
When an Earthworm borrows itself into the ground it leaves very
small tunnels and allows oxygen to seep into the ground effectively
loosening the soil. Loose soil allows for plants to grow with great ease
because it does not take as much effective energy to penetrate into
the ground. These tunnels also allow for more then just oxygen to
penetrate into the ground. When it rains the ground is very loose
and can effectively hold more water within the ground creating a further
moist environment for the worms as they enjoy and more importantly
plants have more water to tap into.
The worm does not purposely secrete, irrigate, and mix the horizons
together for the creation of great topsoil, but it does this in the essence
of Geology. This shows all the pieces of the worm’s ecology working
together but with an organized chaos of earth’s cycles and how its
particular cycle of top soil is benefited from another cycle. Just a few
of the Earth’s cycles such as the water cycle, topsoil cycle, and earthworm
life cycle shows how each of these are different but help each other in a
global cycle of its massive perpetuation of the ‘Earth’ cycle.
In conclusion the Earthworm benefits the A horizon and B horizon greatly
by creating a hearty topsoil made of a high Nitrogen concentrate which
is great for Carbon based life. The mixing of the two horizons makes thick
topsoil and allows for greater root penetration into the ground for the
key topsoil ingredients for plant growth. Lastly, the aerating the worms
leave in the ground help the oxygen and water reach key parts of the
soil to help growth. These three key combinations the worms do in
their interaction of the soil allow or great growth. While they are not
the purposeful effect the worms are trying to achieve, they also benefit
from these benefits as well. They benefit by the moist environment
the aeration creates and when the plants grow, they die decompose and
create even more food for the worms, creating even better soil for more
plants to grow. This shows two earth cycles working together forming a
new unique cycle.
Facts about Earthworms
These critters are underground farmers who turn over the soil like a plough.
In just one acre there can be a million or more of them, eating 10 tons of
leaves, stems, and dead roots a year and turning over 40 tons of
soil in the process.
There are 4,400 different species of worms.
There are 2,700 different kinds of earthworms.
The tunnels created by the worms help plant growth by aerating the
soil allowing for better water penetration.
The earthworm lives on average one year.
Worms fertilize the soil with their castings, which contain the recycled
nutrients from the debris they eat.
Many earthworms are not native to the United States, most were
introduced from Europe.
Earthworms do not have eyes, but are light sensitive.
Sunlight will kill earthworms.
Interesting Facts about Earthworms. PilePro Compost Bins. Composting 201.
Worm Facts. Interesting things to know about worms.
Fun Earth Worm Facts.
Biology 203 Lab. Protostomes.
Common Earthworm. National Geographic. Jason Edwards.