Monday, August 11, 2008

Experiments to Save the World (I)

Sandstorms: a totally marine phenomenon
Conducted by: Boss1
Karenne Tun, Research Assistant, NUS Marine Bio Lab


There are many things at the bottom of a coral reef.
1. Animals [eg. Stingrays, fishes, sea urchins, sea cucumbers, coral (yes coral are animals!)]
2. Vegetation (eg. Sea grass, algae)
3. Dead matter (eg. Dead animals and vegetation)
4. Sediment (eg. Sand, silt, mud, fine dead matter)



Sediment is the topic of interest. Marine environments with little disturbance along the bottom will have clearer waters because sediment sinks. The picture below is an example of a beautiful reef. Of course if the disturbance increases or by some magical means sedimentation (deposition of sediment) occurs then the waters would be less clear.
Illustration as below.

An illustration: A Fun Activity

Create your own pristine marine environment! Get a clear plastic bottle, add in about 2cm of beach grade sand and fill with water; clear waters with undisturbed sediment. If want of more chaos give the bottle a good shaking. The result is a ‘smoothie’ otherwise known as murky water. Leaving it to stand would cause sedimentation where the sand is deposited on the bottom of the bottle.

Imagine adding 2cm of sand into that bottle everyday. Imagine placing your pet goldfish in that bottle and dumping sand on him everyday. Imagine swimming at the bottom of the pool when suddenly you’re drowning in a flood of sand. This is what Singapore’s corals have been experiencing, sandstorms.

Coral possess zooxanthellae (photosynthetic organisms eg. Like plants) which produce food for the coral by photosynthesis (process of making food by light and carbon dioxide eg. Like plants). Note that light is a requirement. How do they survive such onslaughts of sedimentation? Sedimentation would surely cloak the corals from their precious sun.

Coral have an efficient mechanism for removing such filth. MUCUS. Before you run away screaming in horror do not forget it is the human equivalent of blowing your nose. Mucus is a fantastic substance. Dirt sticks to it like glue. The sediment coagulates (clumps together) on the mucus which is then swept away by the currents.

Your regular mucus excrements would contain some microscopic dust. Imagine now that dust increasing in concentration tenfold. You would have some major blockage in your pipes. Similar to this analogy, an outstanding amount of sediment would be next to impossible to remove. And daily sedimentation would cause prolific proliferation (mass production) of coral mucus. Please do not think that mucus is brought in buckets by the mucus fairy for all to use happily ever after, mucus is an organic substance it is produced by the organism and therefore coral need to spend more energy producing more mucus. It is the equivalent of a student working 15 extra hours each day instead of spending it as developmental time eg. Sports, R&R, sleep.

And thus a question is born out of the mind of Karenne Tun aka Boss1. What level of sedimentation can corals take before they die? The hypothesis is practical, the experiment grueling and the conclusion prudent. With a quantity for coral deaths (rate of sedimentation), the people managing the people who cause sedimentation can put a check on the amount of sediment being introduced into Singapore waters.

Singapore with our magnificent biodiversity and 249 species of coral [1], will surely be an extraordinary diving and snorkeling location. If the results from research like this are made into practice our reefs might not need to weather such sandstorms again

References
[1] Hope for coral reefs here: just one species gone; concerted effort can reverse extinction trends
By Shobana Kesava
The Straits Times, Saturday, August 16 2008 PPB9

Picture of pristine site by Karenne, Poisoned goldfish by Theo and Mucus illustration by Jacque

No animals were harmed in the making of this article

Jacque and Theophilus finished work at 1:12 PM

______________________________

the marine junkies
Jacque and Theophilus
18071990 / 28081990
NUS High School
NUS Marine Biology Labs

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Nudibranchs drawn by Prof. Chou
(hand drawn! wow!)
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