Originally Posted by Chesherca
So what I'd like to learn from those with more understanding of such things is if
I would be able to keep this algae alive indefinitely in a small container, and what I would have to do to make that happen.
We all know that algae, like anything else in our tanks, is alive and needs the basics to stay alive: a food source (which is light in most photosynthetic creatures), gas exchange and an enviroment suitable for that specific creature. The food source is a bit tricky with photosynthetic creatures since just light may be good enough, but other nutrients will help it thrive. These are the things that we try to avoid in a tank; things such as nitrates, phosphates, silicates, etc always increase algae growth. Gas exchange is important since carbon dioxide is a big ingredient in photosynthesis. You will need something to exchange gas with the algae (carbon dioxide for oxygen). The enviroment suitable for algae growth will be taken care of, since I assume you will be using water...
I think that Water Change water from an existing tank may be the best way to keep this alive. I couldn't watch the video (I am at work and they are not too keen on my fishkeeping hobby...), but from your post I assume that this needs saltwater
to survive. I would say (as an experiment) use tank water from a water change out of your freshwater tanks and add salt mix (I use Instant Ocean. Do not use aquarium salt, it's not the same thing). This would provide the nutrients, such as phosphate and nitrate, to promote algae growth, and the water might be higher in Carbon Dioxide because it was lived in. I don't think that you would want to subject a fish to the kind of water that you will be adding to this experiment, so I don't think that using a fish for gas exchange would be a good idea...
THat is all I have. Hope this helped!