Science Buddies: "Ask an Expert"

Hey guys!
I want to do something in Ocean Acidification in reponse to the Global Warming Changes, but I am having a hard time finding a project that works for me. I want to do something that challenges me, but doable with access with a school lab. I have read about experiments with calcium carbonate deterioration and the dinoflagellate bioluminescance with decreasing ph, but I want to build on that somehow. Do you have any ideas?

Sincerely,
nni2

Hi nni2,

A project on ocean acidification would be very timely and important now as CO2 emissions continue to increase. What question do you want to ask? When I think of detrimental changes to the ocean, I think of the possible effects on the phytoplankton because that is where most of our atmospheric oxygen comes from. Kill off all the photosynthetic organisms and we lose our air supply.

What is the effect of excess atmospheric CO2? As you said, the CO2 from the air dissolves in sea water and this produces carbonic acid which lowers the pH. However, phytoplankton use dissolved CO2 for photosynthesis, so in that sense more CO2 is good for them. But what about acidity? Too low a pH would surely kill dinoflagellates—but what is too low? How high would atmospheric CO2 levels have to be to decrease the ocean pH to a level that affected the growth of phytoplankton or more importantly, their ability to produce our oxygen?

These are all potential questions that could be studied. Here’s a link to an article in which a dinoflagellate and a cryptophyte were tested for growth at reduced pH: http://www.int-res.com/abstracts/meps/v416/p79-91/

The authors concluded that these phytoplankton were resistant to the lower pH, but that this only represents a small part of the total population and other species, especially those in the ocean away from the coast may respond differently. You could do some similar experiments with different species and measure their oxygen output which really is the critical function. The plankton may survive lower pH, but if they can no longer produce oxygen then we are in trouble.

Let me know your thoughts about where you would like to go with the project and we will try to steer you in the right direction for success.

Best wishes,

SciB

Thank you so much for the quick reply, it really helped! I finally decided on doing a project with coral on ocean acidification, but I need to find a source to buy an abundance of coral for a small price. Do you know anywhere where I could get it?

Hi nni2,

Are you planning on using living corals that can be grown in a salt water aquarium or dead coral ‘skeletons’? Here’s a site that has some really pretty live corals that you can buy by mail http://www.liveaquaria.com/product/aqua ... .cfm?c=597

You can get a mixture of salts called Instant Ocean at big pet supply stores and use it to set up a salt water aquarium.

If all you want are dead coral than you should be able to buy that online. I found one site that sells coral pieces that are inexpensive-- http://deltonaseashells.com/coral---bar ... 7AodXGQAYQ

I hope this helps. If you have more questions, let me know.

Best wishes,

Sybee

Hi! I'm really interested in working with phytoplankton and the effects of ocean acidification, but I'm not sure how to even design my experiment. Would I have to buy phytoplankton? Where do I even buy them? Your ideas really intrigued me!

Hi,

You may want to take a look at this thread for some more info and ideas on how to grow phytoplankton:
https://www.sciencebuddies.org/science- ... php?t=2189

Here is another website that teaches you how to grow algae:
http://www.education.com/science-fair/a ... ing-algae/

You can purchase and culture the algae or collect a sample from somewhere such as a pond. If your school has a spectrophotometer, you could use it to quantify growth by measuring light absorbance. You could also count the number of cells with a microscope.

I hope this helps,
Derek