Culturing Phytoplankton.
To feed rotifers for feed for fish larvae and for growing Artemia to adulthood.
We are culturing Nannochloropsis (NAN), NAN is the best algae for rotifers and high in EPA;
Equipment Set-Up
Fluorescent light or 40 Watt daylight fluorescent bulbs, I find 6500k bulbs the bare minimum for optimal growth and penetrating a dark green culture. On 24hrs a day.
Air pump.
3 metre. Flexible airline tubing.
1 metre. Rigid airline tubing.
Multi-outlet airline splitter/valve.
clear plastic or glass bottles.
Aquarium salt or natural salt water.
f/2 Formula used at 5 drops per litre of water.
Phytoplankton starter culture, Nannochloropsis occulata.
Mount the fluorescent light or bulbs so it is about ½ the bottle height to give maximum light exposure to the plankton.
Spread your culture bottles out to maximize surface area exposed to the light
Drill 2 holes in each bottle cap just big enough to push the airline through, 1 for air in and the other out. In this picture there is a Frit on line in to ensure clean air supply and out line is filtered to ensure no cross contamination on air out.
Cut a length of rigid tubing to reach the bottom of bottle and fix to the in line flexible tubing, this then attaches to air valve or pump.
¾ fill each bottle with salt water diluted to SG 1.015,
Turn on air pump and make sure all 3 airlines create a modest flow of bubbles. Adjust flow rate on splitter as necessary to create uniform moderate flow in all bottles.
I culture my algae on a water bed heat pad or mirror demisters. set at 24c degrees, In summer i can turn the heaters off
I use fresh NSW that has been filtered through coffee filter paper and autoclave (super heated) then diluted to SG 1.015, fertilized with f/2 media at the rate of 5 drops per litre. You can sterilize overnight with bleach, 1.5ml/6L and dechlorinate with thiosulphate.
I keep stock cultures in 1 litre sterilised soft drink bottles that are kept in the fridge, and used according to needs.
A bottle reaches peak growth in 10-14 days and it is then harvested.
New pure cultures are seeded approximately every 9 days, with each culture agitated each day.
Take it slow in the beginning, allow your culture to take-hold and keep possible contamination at bay. Once your culture has reached a deep green colour you are ready to subdivide.
Grow-out and Harvest
Once the culture is up and running, you will need to establish a separate culture in a few different bottles. Pour 1/3 of the culture into each of 2 new bottles, so that there is 1/3 in all three. Fill them back up with fresh media, set them in front of the light and get ready to harvest in a week. From then on out, harvest 2/3 of each bottle, keep the remaining 1/3 in the original bottle and top-off with new media. Put the airline back in and you’re culturing like a pro.
Storage
Use the phytoplankton immediately or store it in the refrigerator until it is needed. If storing the phytoplankton for longer periods of time, you’ll notice that the phytoplankton cells settle to the bottom–make sure you shake it up at least once a week or the culture will spoil/rot.
Once a culture turns yellow throw it out.