Science Buddies: "Ask an Expert"

Please see! This is another idea that I got!

Anthropogenic aerosols have been reported to be main cause of ozone-depletion and these particles travel up to a very great height. I want to check the effect of these aerosols on plants. Because even if these colloidal particles settle on plants there may be some obstruction to the plants due to which it's capacity to take CO2 maybe decreasing. As we know, the greenhouse effect has come from the original Greenhouse Experiment where a glass house or small structure was taken and CO2 was let in and the graph of photosynthesis started rising rapidly and then suddenly dropped to 0, thus showing excess CO2 is harmful. So how would it be if the same experiment would be tried but with Aerosols instead of CO2 and maybe, it actually does have an effect of the plant. I've tried researching on aerosols and their settlement but I've not found anything about effect of aerosols on plants.
MY TARGET DATE TO FINALIZE A TOPIC IS ON 22-OCTOBER-2014... So in the mean time, I want to tell about any idea I got!

P.S. For the Science in Action thing, can you suggest any topics: like farming or anything?

Please leave your valuable suggestions. Thanks!

Hi Samhitha,

More ideas! Which one will you decide on?

I have to disagree with your first statement, however. Ozone depletion is caused primarily by chlorinated hydrocarbons such as freon and halon: http://www.epa.gov/ozone/science/q_a.html

Manmade aerosols include smoke and soot from power plants and vehicles, sulfate aerosols from burning coal and dust from farming and manufacturing processes. Aerosol particles are very fine and can move long distances although they do not persist for much longer than a week. I got this information from the NASA EarthObservatory site: http://earthobservatory.nasa.gov/Features/Aerosols/

Aerosols can also be naturally produced by volcanoes, dust storms, forest fires and salt spray. In fact, 90% of the aerosols in the atmosphere are from natural sources. This means that manmade aerosols are not especially important.

The major effect of aerosols is to reduce the intensity of sunlight by either absorbing it or reflecting it back into space. The eruption of Mt Pinatubo in the Philippines blasted huge amounts of aerosols into the atmosphere and caused the local average temperature over the next year to drop by half a degree. One could consider aerosols a good thing because they counteract the warming effects of CO2 emissions. However, many aerosols contain pollutants that can damage the environment and be harmful for humans to breathe.

Aerosols could affect photosynthesis by reducing the intensity of sunlight that reaches plants. In the case of a catastrophic eruption of a mega-volcano as some geologists predict, the whole planet could be plunged into a new ice age. Normal levels of aerosols, however, probably have little effect on crop plants.

I think that if you want to study the effect of anthropogenic aerosols on plants, phytoplankton (http://earthobservatory.nasa.gov/Featur ... oplankton/) like Prochlorococcus (http://microbewiki.kenyon.edu/index.php/Prochlorococcus) would be a more likely target. The phytoplankton in the oceans are the main source of the oxygen we breathe as well as being food for a myriad of sea creatures. Aerosols can be beneficial by supplying nutrients that the cells need such as iron, but they can also be harmful if they contain, for example, toxic copper salts: http://www.jstor.org/discover/10.2307/4 ... 4308756391

You can purchase single-celled marine cyanobacteria cultures from Carolina Biologicals (http://www.carolina.com/living-organism ... uestid=639) and the liquid medium to grow them in. They are photosynthetic organisms and you have to keep a light on the cultures while they are growing. You could try adding some copper salts to the culture and measuring the change in cell numbers over time to see if anthropogenic copper aerosols could be harmful to marine phytoplankton.

I hope this gives you a better idea of the importance of aerosols in the atmosphere. You have come up with a lot of good ideas for projects, but now you have to choose. Whatever you decide, we will be right here to advise you on planning the project and working out the experimental details.

Good luck!

Sybee

Sybee has lots of good suggestions for you (as usual!)

The thing about algae is that it is very important for reducing greenhouse gasses, and thus a major global concern. Just wanted to add to Sybee's suggestions and ideas that you could also experiment with terrestrial plants in laboratory/greenhouse settings. E.g., on more local scales, human-released aerosols or airborne particulate matter (the particulate part of aerosols:
http://www.mfg.mtu.edu/cyberman/environ ... intro.html
could impact terrestrial plants in various ways.

An idea: Find an appropriate source of fine particulate matter, develop a method apply it to plants in an experimental setting at different rates, and see if there is a dose response for growth rates or other parameters.

Regardless of what you do, be aware of potential safety concerns. At too high a dose, airborne particulate matter and polluting aerosols could be potentially unhealthy for you and anyone else around when you do the experiment (hence all the concern about urban air pollution ). So ultimately you will want to make sure that your application methods don't result in too much airborne dose to you (this may be another reason to consider aquatic algae, as you could potentially add them directly to the water). But this can be considered as you further develop and design your experiment.

Like Sybee said, keep us posted!
Ben

BenG, thanks.

In a chemistry class, there was discussion about fire-works and how much pollution they contribute to especially in Asian countries where many festivals are celebrated with them. So I just had a doubt: Has there ever been a less-polluting replacement for fire-works in which magnesium is the core chemical involved?
Is it possible?