Mangroves can be killed by heavy or viscous oil that covers the trees’ breathing pores thereby asphyxiating the sub-surface roots which depend on the pores for oxygen. The toxicity of substances in the oil is also lethal.
The organisms among and on the mangrove trees are affected in two ways. First, there may be heavy mortalities as a direct result of the oil. For example, oil may penetrate burrows in the sediments, killing crabs and worms, or coat molluscs on the sediment surface and aerial roots. Second, dead trees rot quickly, leading to loss of habitat for organisms living in the branches and canopy of the trees, and in the aerial root systems.
There was visible signs of the oil in the water...
The oil foamed into brown clouds after it was sprayed...
Even the leaves were coated with oil...
Why Cleaning The Mangroves Is Difficult
Oil slicks enter mangrove forests when the tide is high, and are deposited on the aerial roots and sediment surface as the tide recedes. This process commonly leads to a patchy distribution of the oil and its effects, because different places within the forests are at different tidal heights. Some mangrove forests are virtually impenetrable, and heavy clean-up operations may cause physical damage.
The oil had spread to many parts of the mangrove forest...
There were layers of oil stains on the sand...
The Importance Of Mangroves
Mangrove forests in optimum conditions are one of the most productive ecosystems; for example a net primary productivity of 23.3 tonnes/ha/year and litter productivity of 10 tonnes/ha/year was measured for a 15-year-old stand of Rhizophora at Matang, Malaysia. The litter (such as fallen mangrove leaves) is broken down by bacteria, fungi and herbivores, and the resulting detritus supports food webs including large populations of invertebrates and fish. The calm waters in the forests are ideal breeding and nursery grounds for young fish and shrimps, while the aerial roots, lower trunks and mud surface usually support a varied fauna of oysters, snails, barnacles, crabs and other invertebrates. The upper part of the mangrove trees is an essentially terrestrial environment with a fauna of birds, mammals and insects.
Mangroves are affected by the freshwater and nutrient supply which they receive from their catchment area, and on the other hand have a strong influence on the adjoining coastal waters and associated ecosystems such as coral reefs, seagrass beds and tidal marshes. For example, they trap and stabilize sediment which might otherwise limit the growth of corals.
A thick film of oil coated the roots of the mangrove trees...
Chek Jawa Is More Than A Mangrove
Chek Jawa is a cape and the name of its 100-hectare wetlands located on the south-eastern tip of Pulau Ubin, an island off the north-eastern coast of the main island of Singapore. Chek Jawa is among the last few places left with a natural rocky shore. The wetlands are unique as several ecosystems can be observed in one area - sandy beach, rocky beach, seagrass lagoon, coral rubble, mangroves and coastal forest.
Sources
