The recent flood happenings have taken a toll on Malaysia and her citizens; more than 240,000 victims were evacuated at one point of time. Kelantan is among the few states that is most severely affected by the flood. Heavy rainfall is usually what comes to mind when we discuss about the cause of these floods. However, let us not forget other factors that when coupled with the extreme rainfall may induce a devastating outcome. For instance, climate change, deforestation, tidal influence and blockage of drains are few factors worth mentioning; all these factors except tidal influence are man-made. As a result of these floods, not only our land but our oceans are to bear the consequences gradually.
The list that states the impact of major floods does not just end at the destruction of land where victims reside. The intensity of the flood water swipes, destroys, and carries excessive amount of sediments, wastes, nutrients, land-based toxic and massive amount of freshwater out into the ocean. Ever wondered, what happens next? The cascading impact from floods is catastrophic. In the end, everything will be dumped into the ocean, burying and smothering one of the most productive ecosystems on the planet— coral reef.
Hard coral is a unique organism that possesses zooxanthellae, a type of symbiotic algae, in its tissues which allows it to photosynthesise. Through photosynthesis process under the presence of sunlight, it is able to produce underwater skeletal structure framework that forms reefs, hence the name coral reef. Coral grows very slowly, from a few millimetres to only a few centimetres per year. It took millions of years for the corals to grow to the current state of diversity. As such, coral is very fragile and sensitive. Any harm on coral will take years if not decades to recover, given that no interruption of major disturbances between this period.
The major flood causes sudden influx of excessive sediments increases water turbidity which reduces the amount of light penetrated into the water. This hampers the photosynthesis process of the coral. Sediments that smother on coral surface causes abrasion on its tissues, thus killing it. Excessive freshwater plumes reduce water salinity which further induces stress on coral. In fact, the 2011 major flood in Queensland, Australia had caused a 99% increase of mortality rate in coral population (Tan, Pratchett, Bay, & Baird, 2012). On top of that, flood fuels the growth of macroalgae, a major foe of corals. These macroalgae will eventually outgrow the number of corals and compete for habitat at the same time impeding the coral larvae settlement. Under these circumstances, coral reef has little chance of survival. The collapse of coral reef will affect the diversity of other marine organisms, risking the depletion of our ocean food sources.
At present, 19% of the corals worldwide have lost beyond recovery while another 60% face imminent threats from human activities (Burke, Reytar, Spalding, & Perry, 2011; Wilkinson & Salvat, 2012). Coupled with the recent major floods, corals suffer from immense stress. While we bemoan for the loss of homes, food shortage and lack of clean drinking water for our fellow countrymen, the impact that lies beyond the coast may cause further misery when we realize our marine food sources become scarce. There is another possible risk – sudden bloom of harmful algae that are toxic and poisonous to our seafood.
In a nutshell, floods indeed have impacts way beyond what is on the land; they also cause destruction of lives out in the oceans such as our beautiful coral reefs, creating a domino effect. It is our duty to understand that the destruction is not limited to what we see at the place of the flood happenings. The reason is because our ecosystem is one highly interconnected system in which living and the non-living organism interact with each other uninterruptedly. Therefore, the important message to take away here is the awareness that although we think that the steps we take are insignificant, they have more significant impact on others than we may ever imagine.
- Burke, L., Reytar, K., Spalding, M., & Perry, A. (2011). Reefs at Risk Revisited. Defenders (Vol. 74, p. 114).
- Tan, J., Pratchett, M., Bay, L., & Baird, A. (2012). Massive coral mortality following a large flood event. In Proceedings of the 12th International Coral Reef Symposium (pp. 2010–2013). Cairns.
- Wilkinson, C. R., & Salvat, B. (2012). Coastal resource degradation in the tropics: Does the tragedy of the commons apply for coral reefs, mangrove forests and seagrass beds. Marine Pollution Bulletin, 64(6), 1096–1105.
Written by : Edmund Lau Chai Ming
Editted by : Roxanne Low