Tsunamis and natural disasters

The recent tsunami in Japan on March 11, 2011, caused an enormous loss of life and devastation to coastal cities and villages in Japan. The impact of a tsunami on the ecosystems in the ocean surrounding the tsunami also result in tremendous damage and loss of sea life. Yet this devastation often goes unreported.

The initial result after the underwater earthquake is the drawback. This is when the water recedes and much of the ocean floor is exposed. This exposure results in the death of the sea creatures and plants on the ocean floor. Following this event, a large tidal wave forms and the power and force of this wave destroys everything in its path. If you saw video footage of the approaching tidal wave you will remember that it was already brown, probably due to the scouring effect of the wave on the ocean floor as it comes towards land. Finally, when the flood starts to return to the ocean a huge amount of debris including vehicles, building materials, deceased livestock and humans returns to the ocean and pollutes the water. Increased toxin levels in the water have not yet been measured but this most likely effects the ecosystems in the ocean. The impact that this has on the ocean ecosystems is still being researched although we can all assume it must be large.

In an article following the Southeast Asia Tsunami in 2004 the author states " man was not alone in feeling the impact. Ecosystems and other species were also hit." Coral reefs act as natural shock absorbers during a tsunami, but in the process have seen large-scale destruction during these natural disasters. The increased sediment surrounding sea grass beds and oyster reefs that remain intact after a tsunami have a great impact on the many different creatures that feed and live off these areas.

Interestingly, the supply of fish in areas badly hit by the 2004 tsunami such as Sri Lanka and on the Thai coast has increased since the tsunami, mostly due to the fact that more than 13 000 fishermen and over 4 500 fishing vessels were lost. As a result of this loss of fishing capacity, fish stocks have increased. One positive impact following such a devastating natural disaster. Tsunamis and hurricanes are two natural disasters that cause a change to the fragile ecosystems in the ocean.