Coral bleaching in Taiwan

Problems

• Taiwan is home to a diversified coral ecology that is rarely seen in other subtropical areas around the world. However, as the climate is getting hotter and breaking historical records, Taiwan is seeing widespread coral bleaching in its oceans. 
  
  Corals are animals with colonies of many identical individual polyps, which are tiny, soft-bodied organisms. Most of them are transparent. The riot of colours that we see come from the algae called zooxanthellae that provide photosynthetic nutrients and form close biological interaction called symbiosis with the corals.
  
  Taiwan used to be known as the coral kingdom. The coral reef communities are widespread in Kenting, Green Island, and Orchid Island. These communities make up less than one-thousandth of the world’s coral reefs in terms of scale, but in terms of the variety of species,  they make up one-third of the world’s total. Of the 700 species of stony corals on the planet, 250 species can be found along the coast of Taiwan! 
  Corals are the longest-living animals. 

• Causes of coral bleaching in Taiwan

  Changes in environmental conditions, such as 
  - water temperatures, 
  - pH values
  - turbidity 
  will directly affect the symbiotic relationship between corals and zooxanthellae. When the living environment is not optimal, the symbiotic zooxanthellae will gradually leave the corals or will be expelled by the corals, leading to the corals losing their colour sources and gradual bleaching. 
  
  After the symbiotic algae leaves, the corals will not die immediately. If the environment becomes better, the bleached corals can regain the zooxanthellae and slowly recover for survival.   However, if they bleach for a long time, the corals will gradually weaken and die. Therefore, coral bleaching is the last distress signal for corals. 
  
  With the drastic changes of climate in recent years, global warming has caused seawater temperatures to rise. The greenhouse effect has also caused ocean acidification that weakened coral’s absorption of calcium carbonate, which is made of coral’s skeleton. When coral reefs are not strong enough to resist natural erosion it will take longer for them to recover from bleaching. 
  
  In addition, terrestrial and marine pollutants due to human activities can easily cause harmful impacts on coral reefs, such as agricultural pesticides flowing into rivers, industrial and household wastewater discharged into the sea, and even sunscreen products because they contain chemicals like Benzophenone and Octyl methoxycinnamate that will disrupt their reproduction and growth cycles. 
  
  "In the face of the unusual increase in seawater temperature caused by climate change, more ambitious carbon reduction targets should be set by the Taiwanese government to replace fossil fuels with sustainable energy and slow down global warming" - Greenpeace believes.