Pediastrum
boryanum is one of many species of tiny plants that are
called "green algae." Actually, any species
in the Chlorophyta Division (phylum) is called green algae.
Green Algae come in many different shapes and sizes.
Pediastrum boryanum is the scientific name of one
green algae species.
To see one Pediastrum
boryanum you will need a microscope. If many
Pediastrum boryanum are together, probably with other
species of algae as well, they will look like green slime in
the water.
Peter v.
Sengbusch
Y. Tsukii
What you see in the
pictures are actually colonies of Pediastrum
boryanum. Colonies are circular, star-like shapes,
usually made up of eight, sixteen, or thirty-two individual
Pediastrum boryanum. Smaller colonies with two or
four Pediastrum boryanum don't stay that way long,
because they grow fast. Sometimes there can be more
Pediastrum boryanum in a colony, but not very
often.
Pediastrum
boryanum colonies are green and float around in ponds,
marshes,
lakes, pools, and rivers.
The reason some colonies
look greener in some of the pictures than others, is because
some of the colonies are in the process of making more
Pediastrum boryanum. The ones that are not fully made
yet, look like they're not "filled out."
Copyright, John
Kinross
Each prickly little shape in the
colony is an individual organism.
Pediastrum boryanum have only one cell,
but just like larger plants, such as trees, they can make
oxygen.
This is important for animals, and for us, since water must have
oxygen in it in order to stay water. Underwater animals with
gills,
such as fish and tadpoles,
need to breathe oxygen through water. Other animals, including
people, need to drink water to survive.
The way Pediastrum boryanum
make more Pediastrum boryanum is when, one at a time, each
Pediastrum boryanum cell in the colony releases tiny things
called zoospores. Zoospores leave the colony and make a new colony.
Each Pediastrum boryanum in a colony releases zoospores at
different times, so that a colony is almost always making new
colonies.
How fast algae grows depends on
how much light it gets, the temperature, and amounts of
nutrients
in the water. Like other plants, algae can make their own food. To do
this, they must have light to complete the process called
photosynthesis.
Algae can grow faster in warmer temperatures. Even though
Pediastrum boryanum lives in water year-round, it does not
grow nearly as fast in Winter as it does in Summer. Different bodies
of water have different nutrients in them. Like all plants, algae
needs to absorb nitrogen. One thing that provides nitrogen is animal
waste (poop). Therefore, algae helps all organisms by taking in waste
(poop, dead animal and plant matter) from the water, providing
oxygen, and by being a food source for animals.
One way that Pediastrum
boryanum and other green algae are able to spread from one body
of water to another is birds. When ducks, geese, herons, or other
water birds fly to new areas, they carry mud on their feet. Inside
the wet mud, algae can survive until it lands in a new body of
water.
Animals that eat green algae
include frogs and salamanders (tadpole
and larval
stages), crayfish, aquatic
insects, snails, some fish, water fleas, mussels, amoebas,
paramecium, water bears, and many others.
Pediastrum boryanum cannot
move on its own. It stays with its colony and floats with currents in
the water. When many colonies in the same area stick together, they
provide cover
for fish, aquatic insects, and other animals.
Pediastrum boryanum helps
controls Zebra Mussels. Zebra Mussels were introduced from another
country and have become a terrible pest. They are smaller mussels
which attach and cover larger native mussels, making it difficult for
them to move and eat. Zebra Mussels often kill our native mussels,
such as the Eastern Lamp Mussel, this way. Pediastrum boryanum
colonies clog the filters of Zebra Mussels so they can't eat.
Therefore, Pediastrum boryanum helps our native mussels and
our aquatic habitats. Zebra mussels have not shown up in Virgina yet,
but they are a huge problem in other states and scientists believe
it's only a matter of time before we have them too.
As mentioned above,
Pediastrum boryanum and
other green algae are important because they convert nitrogen from
waste into a form other animals can use. Large amounts of algae in a
body of water is also a sign that the water may be polluted. Since
green algae does so well in water with lots of waste, there is a good
chance that water is polluted when you see a lot of algae. Scientists
use this information to identify polluted waters and to try to figure
out ways to clean them up.
