About Algae
ALGAE
What are blue-green
algae?
Cyanobacteria is the
scientific name for blue-green algae, or "pond scum." The first
recognized species were blue-green in color, which is how the algae got
their name. Species identified since range in color from olive-green to
red.
Cyanobacteria
form in shallow, warm, slow-moving or still water. They are made up of
cells, which can house poisons called
cyanobacterial toxins. A
mass of Cyanobacteria in a body of water is called a bloom. When this
mass rises to the surface of the water, it is known as
surface scum or a
surface water bloom. The
arrival of spring often presents a problem for pond owners as the
beautiful, clear green water of their ponds disappears beneath a blanket
of lime green, slimy, stinky pond scum. "Pond scum" is actually a
popular term for aquatic algae, which tend to "bloom," or grow
excessively in the early months of spring, spreading over the surface of
the pond in unsightly and odorous mats of green and brown.
For us there are
two large groups of algae which are important. These are the floating
and the string algae.
Floating algae
are uni-cellular and rather float in water and give it a
green appearance. At larger concentrations of floating algae it is
possible water becomes so turbid that it becomes untransparent. Dead
floating algae drop on the floor and sites
and cause greenish mats.
String algae
are uni-cellular as well, but because they join to each other, they can develop into large constructions. Their appearance can vary from thread-like on obstacles under the waterline to vast clouds of strings that become up to meters long.
Several
factors
influence
alga increase
in water, namely :
-
Feeding substances, especially nitrates and phosphates in
water can cause explosive increase of algae.
-
An indispensable factor for the algae is light for algae that
practice photosynthesis. This is the most common type.
-
In dark surroundings (water tanks) we also find algae, but they
are generally considered as part of the biofilm.
-
Temperature: At 4°C algae start to grow. Their optimum
temperature is 25-30°.
- Movement: Floating algae thrive best in stationary water. String algae on the other hand manage strong water movements, think of algae increase on water falls and algae attached to boats.
BIOFILM
A
biofilm is
a complex aggregation of microorganisms marked by the excretion of a
protective and adhesive matrix. Biofilms are also often characterized by
surface attachment, structural heterogeneity, genetic diversity, complex
community interactions, and an extra-cellular matrix of polymeric
substances.
Single-celled organisms generally exhibit
two distinct modes of behavior. The first is the familiar free floating,
or planktonic, form in which single cells float or swim independently in
some liquid medium. The second is an attached state in which cells are
closely packed and firmly attached to each other and usually a solid
surface.
Biofilm grows
best in slightly polluted water. The presence of nutrients stimulates
the shaping of biofilm. However also in controlled water systems there
is biofilm growth.
Also pathogenic
micro-organism develop in the biofilm . Certain biofilm even deliver
corrosion stimulating substances such as organic acids or sulfide
by-products. The presence of biofilm can disturb the functioning of
valves and pumps and decrease the productivity of heat exchangers
A biofilm is a complex aggregation of
microorganisms marked by the excretion of a protective and adhesive
matrix. Biofilms are also often characterized by surface attachment,
structural heterogeneity, genetic diversity, complex community
interactions, and an extra-cellular matrix of polymeric substances.
Single-celled organisms generally exhibit
two distinct modes of behavior. The first is the familiar free floating,
or planktonic, form in which single cells float or swim independently in
some liquid medium. The second is an attached state in which cells are
closely packed and firmly attached to each other and usually a solid
surface.
Biofilm grows
best in slightly polluted water. The presence of nutrients stimulates
the shaping of biofilm. However also in controlled water systems there
is biofilm growth.
Also pathogenic
micro-organism develop in the biofilm . Certain biofilm even deliver
corrosion stimulating substances such as organic acids or sulfide
by-products. The presence of biofilm can disturb the functioning of
valves and pumps and decrease the productivity of heat exchangers