The Blue Tempeh
Wednesday, June 29, 2005
  Adopt a reef, and save the coral
An article published on the 28th of July in the Straits Times:

Adopt a reef, and save the coral
By Chang Ai-Lien Science Correspondent


MAKE SURE YOU HAVE READ THE ARTICLE BEFORE PROCEEDING WITH THIS BLOG...if not, it will just look like another one of my ramblings. Heh.

Read it? Sounds massive eh?

Anyway, to give you a better idea of what an REU looks like and what it IS and what it can DO, here it is:

A 3-year old REU with naturally recruited Pocillopora sp. corals growing it, among other things.

You might think, "OH MAN, SO BARE! Just a few of those rock things!" But to me, it looks impressive. Corals are slow growing, and to see so many colonies doing rather well on these Reef Enhancement Units (REUs) a.k.a. (as now known) Reef Homes (basically artificial reefs), is quite heart warming! It truely is...

Here's more photos of baby corals (my FAVOURITE-MOST-THING to see when diving...):

An Acropora sp. coral growing on a 3-yr old REU. I think this baby coral is about 2 years old and about 5cm wide...BUT IT ALREADY HAS THE CUTEST PORCELAIN CRAB LIVING ON IT!!

Favites sp. coral also on a 3 yr old REU. About 6cm wide. I love this one because it's so fluorescent!

The point is, these REUs a.k.a. Reef Homes, DO WORK. I was a skeptic to begin with when I had a hand in doing a project involving these artificial reefs. I didn't really think they'd be any better than natural substrates like dead coral rubble, which make up a substantial portion of our reefs of late.

But, seeing it for myself, following the life of some these REUs from the beginning, I began to believe. These REUs provide a more stable environment for coral recruitment compared to natural dead coral rubble (which consist of small-ish unattached pieces of dead corals). Although I agree more proper studies are still needed to evaluate the performance of these REUs, so far, it looks quite good.

A rubble patch. Because rubble patches are normally horizontal, they trap sediments that can smother the corals. Rubble make up a substantial part of our Singapore reefs nowadays. The REUs' mostly vertical surface discourage trapping of sediments.

REUs can also be home to other marine creatures, such as hydroids and anamones as seen here. It can also provides shelter for fishes and other marine organisms.

So far, I have been telling you what REUs CAN DO. They CAN provide a nicer home for baby coral compared to rubble areas on Singapore's reefs. They CAN artificially contribute to structural complexity of the reef (shapes, structures, i.e. places to hide for fish and other marine life). They CAN therefore POTENTIALLY aid in the "restoration" and "rehabilitation" of damaged reefs.


The reason why the words restoration and rehabilitation are in inverted comas (" "), is because it is IMPOSSIBLE to fully restore and rehabilitate reefs. We have lost over 60% of our coral reefs, we can't possibly restore THAT.

And most of our remaining reefs have lost up to 65% of their live coral cover...THIS, we might be able to rehabilitate. But it would take a MIRACLE if the conditions of our marine environment and waters remain the way it is NOW.

The amount of sediments in our waters have increased TEN-FOLD of more since the 1970s. Our water visibility has dropped from, on average, 10m to about 1-2m. On some really bad days, the vis can drop to less than 20cm. But on good days, 4-5m. (If you want to know more about BAD and GOOD days and how I define them, email me at If not, the Blog will be too LONG.)

All these means that light, needed for the algae in the corals to make food that the coral also uses (see PAST BLOG: What you need to know about corals), is not able to penetrate and reach the corals and zooxanthellae in the corals. The corals will literally die of starvation.

Worse still, when the sediments SETTLE onto the corals, it can also smother the corals.

Handful of silt from the silt layer characteristic of Singapore's reefs.

OK OK, so you've heard all these before. You know all these. But WHAT DOES THIS HAVE TO DO WITH THE REUs?! These REEF HOMES, these artificial reefs that will supposedly help recover our lost coral reefs.

Well, it has EVERYTHING to do with the REUs. The point of the REUs is to recruit all these corals. And to have corals, in a few decades (your children's and grandchildren's time), fully colonise the REUs and our reefs to be full of corals again!

But if we put a couple of thousand of these REUs down and STILL have our waters as sedimented as it is (as dredging and reclamation works continue), you CANNOT expect the REUs to do their job! WE, as Singaporeans, as the public, have to also ensure that the surrounding conditions are CONDUCIVE for corals SETTLEMENT and RECRUITMENT (baby corals are moving plankton when very young, and then attach onto the substrate and grow to resemble the corals you see and know of) and GROWTH.

Dying Pocillopora sp. coral on a 1 yr old REU placed on the reef of Kusu Island. Waters need to also be conducive for coral recruitment and growth for these REUs to do their job.

The cost you ask? $360 is not a lot if you consider it as an investment for the marine environment for your kids and grandkids. That's why I think it's rather worth it. But if you're going to invest in this, as an investor, you have the RIGHT and RESPONSIBILITY to make sure that your investment thrives. To take interest to ensure that your efforts for marine conservation is not wasted.

REUs at Kusu Island. The vis that day was 4m. This photo has not been edited. When these were first deployed, the vis was 0m. I REPEAT ZERO. Due to reclamation works at the surrounding islands. Water is dynamic. Even if reclamation/dredging is not taking place at that particular reef, it WILL affect surrounding reefs.

On reefs where the water conditions are better and there is good documentation of coral recruitment, such as reefs of Raffles Lighthouse, these REUs have been shown to work wonderfully. So I PERSONALLY feel that to make the REUs work, a campaign for clearer, cleaner (less sedimented) waters is truely needed. PLUS, wouldn't it be nice to look down the jetty at Pulau Hantu or Kusu or Saint John's and have water so clear you can see the corals and marine life? It would do wonders for Singapore's image as a city: not only a GREEN CITY... but also a BLUE one...

Our reefs are still rich. As I myself and many others have documented. Bountiful in a diversity of marine life and corals. So I too feel that there is a good chance for recovery. But you can't just slap on a plaster and expect a wound to heal on its own. You need to clean it first, just like you need to clean/clear our waters first before corals once again take a foothold on our reefs.

REUs on reefs of Raffles Lighthouse (Pulau Satumu). 4-5m vis.

With such a big project ("Adopt a reef, and save the coral"), hopefully people will take more interest in our marine areas. Aware, informed citizens make good and active citizens. You have been informed (hopefully), what are YOUR opinions?
hello! thanks for your letting us interview u today! u realli helped us alot.
~ ie zhi (i was de guy asking the questions)
do you mean 28 june? :)
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