Download Algae - City of Belmont

Ci t y o f Be l m o n t
I n f o r m a t i o n Sh e e t - A l g a e
What are Algae?
Algae is a collective term for plant-like micro (small) aquatic organisms which are either single celled or multi celled
organisms. These organisms grow using the sun to create their own energy. Algae occur naturally in water bodies
including our lakes, rivers and wetlands and can appear to be free floating or attached to rocks or other surfaces.
Algae range in colour from greens to browns and vary in appearance and shapes with some existing as single cells
and others grouping together in colonies. These plant-like organisms play an important role in the aquatic ecosystem.
Algae are an essential part of the food chain supplying food to aquatic insects, fish and crustaceans and assist in
keeping the environment balanced. Algae also, like plants, generate oxygen when they photosynthesise. Common
species which naturally occur and bloom in our lakes are Spirogyra and Compsopogon.
Figure 1: Filamentous - form colonies
What are Algal blooms?
Algae blooms occur when the aquatic ecosystem in
which they exist becomes unbalanced. Blooms
generally occur over the warmer spring-summer
months where light duration has increased as well as
temperature. Warm waters promote the growth of
algae and with increased nutrient levels within the
ecosystem rapid growth occurs. Blooms are most
noticeable when ecosystems become smothered in
algae which form mats covering the bottom or surface
of the water column or when there are so many cells it
literally turns the water green. These blooms will
decrease with cooler weather, when the nutrients
available have been exhausted or with an increased
flushing or mixing of water.
Are Algae and Algal Blooms harmful?
Algae and algal blooms can pose varying human and
environmental health issues such as fish deaths, loss
of native algae species through competition, toxins
released from certain species, odours and unsightly
City of Belmont – Algae Information Sheet
January 2011
Figure 2: Blue-green bloom - exist as single cells
scums. Generally the species which occur in lakes and
wetlands within the City are non-toxic and not harmful
to human or domestic animal health. However it is
recommended that all algae is treated as potentially
irritative just like you would treat most plants. Some
species however are toxic to humans and animals.
When these blooms are identified the City erects signs
to inform people to be cautious around these areas.
The most common type of toxic algae are blue-green
algal blooms which occur in lakes and the Swan River
around the summer months. When these blooms are
sighted it is important not to come in contact with the
water and ensure that no domestic pets come into
contact with this water either.
If you suspect someone has been exposed to or has
consumed water containing blue-green algae seek
medical attention. This includes domestic pets and
animals. When these blooms collapse there are often
odours and scums which will disappear when the
aquatic ecosystem reaches its natural balance again.
City of Opportunity
City of Belmont – Algae Information Sheet
January 2011
City of Opportunity
Does the City manage Algal Blooms?
The management of algal blooms is not an easy task and it is not possible to eliminate them entirely. The City
operates aerators and fountains in most of our feature lakes to prevent the water from stratifying and becoming
stagnant. This assists in maintaining a natural balance in the
ecosystem when the weather warms up and flushing
decreases. The City applies a product called Soilzyme in
lakes which helps the ecosystem naturally use the nutrients
before the algae can bloom.
The City also aims to reduce nutrient run off into lakes and
wetlands by applying best practice for fertiliser use. Physical
removal of blooms is only undertaken in extreme situations
where the bloom threatens to damage aerators and pumps
located in lakes. Physical removal is only possible when the
blooms consist of filamentous algae which have grouped
together to form mats and there is no guarantee that the
algal bloom will not return within a week or two once this is
undertaken.
Do algae have any benefits?
Yes, algae are a natural part of the aquatic ecosystem and the food chain. Algae produce their own energy from the
sunlight and in return provide oxygen to the water column. Algae are also a food source for aquatic organisms such as
water mites, small fish and crustaceans. As they are the first level of the food chain, without them some higher level
organisms wouldn’t exist.
How can we reduce the severity and occurrence of an Algal bloom?
Severity and frequency of blooms are only mitigated by controlling the nutrient supply to the water body and therefore
the algae. Everyone can work toward reducing excess nutrients and pollution from entering water bodies.
Pick up animal droppings from lawns and parks and place them in bins provided.
Please do not feed native wildlife. This can increase faecal waste which affects the water quality. It can also
be harmful to native wildlife.
Always place unwanted garden waste in a green waste bin or take it to the tip or use it as mulch or compost
for your home garden as opposed to fertilisers. Never dispose of green waste in or near a water body.
Wash your car, boat or caravan on the lawn as opposed to on the street or in the driveway and use
phosphorus free detergents. This prevents chemicals and excess nutrients from entering waterways through
the stormwater system.
Use fertilisers in moderation and follow the instructions carefully or seek alternatives. For more information
visit www.fertilisewise.com.au.
If you see any pollution or suspect any, please contact the City as soon as possible with as much information
as possible.
City of Belmont
Parks and Environment Department
215 Wright Street Cloverdale WA 6105
Ph: (08) 9477 7222 Fax: (08) 9478 1473