Science Buddies: "Ask an Expert"

My project deals with finding a way to maximize algal photosynthesis without causing an algal bloom. Some scientists believe that feeding iron to algae in the ocean can help alleviate global warming. The iron increases algal photosynthesis so that the algae consume more carbon dioxide and produce more oxygen. But one problem with this theory is that iron also causes algae to bloom and grow more abundantly so they block sunlight for sealife below.

I would like to conduct an experiment attempting to use iron to maximize algal photosynthesis without causing an algal bloom. I will use one type of algae and add iron to it (iron acts as a catalyst for nitrates and phosphates increasing photosynthetic rate and growth). I hope to minimize the algal bloom by removing either sugar or oil from the algae, or by adding magnesium silicate hydroxide (talc). (I have read that removing sugar will minimize algal growth, while removing oils will reduce buoyancy and encourage the algae to use the energy it makes in photosynthesis for the production of oil to keep it boyant, rather than for growth. Unfortunately, I have not found a way to remove either sugar or oils from algae. I am hoping to find a way to feasibly remove either the sugar or oil in a home experiment. Alternatively I have read adding talc mitigates bloom) I will test the sample of algae without sugar or oil (with talc) against a sample of algae with sugar or oil. My hypothesis is that the unaltered algae's growth rate or surface coverage will be higher than the algae with sugar or oil removed. I thus hope to prove that feeding iron to algae in the ocean can be environmentally beneficial if sugar or oil are simultaneously or quickly removed from the algae.

Although I have done lots of online research, I still have the following questions and wonder if you might provide me with any answers:

1. What type of algae should I use? (I plan to order it from Carolina Biology.)

2. How can I remove sugar or oil from the algae? Should I remove sugar, or should I remove oil? Or should I add talc?

3. What type of iron should I add to the algae? Would it be iron(II) or iron(III)?

4. Should I grow the algae in petri dishes under florescent lights on my kitchen counter? Can I test for photosynthesis using PH strips from the pet store? Can I test for the amount of algal bloom by looking at the density and color. I have no access to devices and tools such as a multimeter, a photo resistor, or a laser.

Ryannock,

I'm sorry no one has responded to your post yet. I think everyone was hoping that someone else would have a good answer for you. The short answer is, I don't know how to remove oil or sugar from the algae. Is this a procedure you read about in a science article? If so, I suggest contacting the author directly.

One thing you may be able to do is limit the amount of carbon your algae have--this would limit the amount of sugar they could make.

Adding talc sounds like something you could definitely do, and I suggest trying that first.

If you can, use an algal species that is found in the ocean--whatever species was used in the experiments you seem to have read about.

I'm not an expert in biochemistry, but from what I found online both iron II and iron III should work. Perhaps you could use both and a combination (be sure to keep the total amount the same) to see if there are any differences between the iron forms?

If you can grow the algae under natural light or under a plant growth light, that would be best--but flourescent lights should be okay if you can't get anything else. pH is definitely something you'll want to measure, and I would think that you could look at both density and color, though you may have to use a subjective scale. If you do this, I suggest scoring all the plates at the same time so your criteria don't accidentally change.

I hope this helps...hopefully a biochemist or a plant physiologist will chime in and correct me if I'm wrong about anything.

MelissaB wrote:Ryannock,

I'm sorry no one has responded to your post yet. I think everyone was hoping that someone else would have a good answer for you. The short answer is, I don't know how to remove oil or sugar from the algae. Is this a procedure you read about in a science article? If so, I suggest contacting the author directly.

One thing you may be able to do is limit the amount of carbon your algae have--this would limit the amount of sugar they could make.

Adding talc sounds like something you could definitely do, and I suggest trying that first.

If you can, use an algal species that is found in the ocean--whatever species was used in the experiments you seem to have read about.

I'm not an expert in biochemistry, but from what I found online both iron II and iron III should work. Perhaps you could use both and a combination (be sure to keep the total amount the same) to see if there are any differences between the iron forms?

If you can grow the algae under natural light or under a plant growth light, that would be best--but flourescent lights should be okay if you can't get anything else. pH is definitely something you'll want to measure, and I would think that you could look at both density and color, though you may have to use a subjective scale. If you do this, I suggest scoring all the plates at the same time so your criteria don't accidentally change.

I hope this helps...hopefully a biochemist or a plant physiologist will chime in and correct me if I'm wrong about anything.

I would guess the talc removes the oil. Talc may trap the oil/ the oil may stick to the minerals of talc. You could test this with a water/oil mixture and add talc, though this would only be suggestive and not conclusive for the effect of talc on algae blooms.

Louise