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Coral Carbon Crisis part 3

Posted 09/06/2010 at 10:39 AM by Mmckibben

Start At part one!

Interpretation of Data

According to the data given corals began to show signs of stress at a pH of 7.9, and SPS corals begin to die at 7.6. Over all the average plankton per drop went up by about 10% by the end of the experiment. It can be assumed this is happening because the coral polyps were small, and didn’t consume as much plankton. The theory is that when the coral polyps are small, and unhealthy, they have a smaller surface area to catch plankton, thus more plankton remains in the water. The corals health is probably being effected by the pH, since it’s the only variable we changed during the duration


The point of doing this experiment was to discover the pH level at which corals die. In

the end these levels were discovered, and they proved that the hypothesis was incorrect.

It was predicted that the SPS corals would die at a pH of 7.65, the LPS at 7.6, and the

Soft corals wouldn’t die at all. According to the data the SPS corals began to bleach at

7.61. The experiment was stopped at this time to limit the possibility of coral death. The

pH levels to trigger death in the LPS and soft corals are left undiscovered in order to

avoid SPS death. The data that was collected is all that is needed because the SPS corals

are the main builder of reefs, and without them there can’t be a reef.

Unfortunately an experiment like this has many inaccuracies. The main one is pH;

it’s almost impossible to regulate pH to drop by exactly .1 without the aid of expensive

equipment. There are also other chemicals, and environmental conditions that could have

caused the bleaching. An example would be water flow, and the size of the aquarium;

since there are objects in the aquarium, the water flow is uneven through out the

aquarium. This can cause pockets of low or high pH. There was also a limited sample

size of only 9 species of corals. To combat this common species, like Montipora, were

used. The time scale was also a problem, the pH is predicted to drop to these levels by

2100, that might be enough time to adapt, but it’s unlikely. In general it’s hard to

eliminate all the inaccuracies when dealing with living things. All of these inaccuracies

can effect my data in many ways, mostly they can ruin the corals health, and give false

pH readings. Both of these can be serious, because unhealthy corals mean less plankton

consumption, this gives you false trends, and data.

Future Studies

If this experiment was conducted again in the future there are many things that could

be changed. First of all it would have been more effective to have a larger and more

mature aquarium. It would be preferable to have a diverse system that had species only

found in one area. This would simulate a more natural environment, thus giving-real

world results. It would also be helpful to have a pH controller. A larger plankton net

could be used in this larger system; this would create a larger surface area, thus making

the data more accurate. The optimal thing to do is have a larger time frame for this

experiment, or add in the other environmental variables, like climate change, and coastal

siltation. An interesting expansion on this topic would be the effect of hydro turbines on

water flow, and gas exchange. Since the turbines slow down the water, the gas exchange

goes down, so in theory it would lower the pH. It would also be interesting to find out if

pH can affect the corals skeletal strength. Coral skeletons are made from calcium; this

calcium is a base. Lower pH levels means more acid. This acid might have the strength to

dissolve some of the coral skeleton.


A special thanks to:

Linda and Bernie McKibben for supporting this experiment

Aqau Imports for getting me intrested in aquariums

NOAA for doing research on enviormental problems

The Marine Aquarium Council (MAC) for their leadership in enviormental ways to collect, and trade saltwater livestock

Works Cited
“Carbonic Acid.” New World Encyclopedia. April 2, 2008. 7 Oct. 2009. <>.
“Frag Details.” 2009. 17 Oct. 2009. <>.
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“Frag Details.” 2009. 17 Oct. 2009. <>.
Henry, John. “Building a Reef Aquarium Part 4.” Reef Works. Henry, Jhon. 2009. 7 Oct. 2009. <>.
Hunt, Philip. The Marine Reef Aquarium. United States and Canada: Barron’s Educational Series, Inc., 2008.
McNeil, Ben. “Pre industrial to Modern Inter decadal Variability in Coral Reef pH.” Science Mag. Ash, Caroline. 2006. 7 Oct. 2009. <>.
Nilsen J. Alf and FossÅ A. Sevain. Reef Secrets. Neptune City: T.F.H Publications, Inc., 2002.

“What is Ocean Acidification?” Ocean Acidification. 2009. 7 Oct. 2009. <>.
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