Page 3 - Aqua Culture Preview

Page 10
Copyright Wet Paper Publications 2010
Background
Micro algae are small plants which:
• Require light, water and carbon dioxide (CO2) to carry out
photosynthesis and grow.
• Produce a wide range of special fatty acids that eventually
end up in fish.
• Are very important sources of food for a variety of marine
and aquatic plankton and lavae.
• Live and grow in water, a medium that so many other
organisms love to live in.
Problems
Some organisms can be harmful to aquaculture species that
algae are going to be feed to, so it is very important to keep them
out of the growing vessel.
This is possible on a small scale, eg in a hatchery, but is not
possible if the algae are to be grown in an open pond.
Solution
To minimise the risk of infecting the algae with organisms from
the air, a closed container is used as shown in Figure 10.1.
• Filtered air (containing carbon dioxide) is pumped to the
algae so it can grow by the photosynthetic process.
CO2 + H2O + energy -----> sugars + O2
• A readily available sealed access port to allow injection of
nutrients is fitted in the top of the vessel.
Containers
See Figure 10.2. These:
• Should be large enough to grow the amount of algae required
• Made of a sterilisable material
• Made of clear PET plastic or glass to allow light to come into
the algae
Materials
• One PET bottle with plastic screw lid
• 3 mm hand drill
• Quantity of clear PVC 3 mm plastic tubing
• Two air filters
• Golf tee
PROJECT 1.3 MAKING AN ALGAL GROWTH CONTAINER
Figure 10.1 A closed container is used to minimise the risk of
infecting the algae with organisms from the air
Figure 10.2 Materials required Mick O'Connor
Mick O'Connor
See page 116 for equipment
supplier details.