Taiwan is domicile to a diversified coral environmental that is rarely seen in other subtropical areas effectually the world. However, as the climate is getting hotter and breaking historical records, Taiwan begins seeing widespread coral bleaching in its oceans. The Coral Reef Observation System of the National Oceanic and Atmospheric Administration (NOAA) upped the bleaching alarm at the highest stress level in July and August respectively, equally it ways severe coral bleaching and significant mortality is underway.

A Greenpeace Eastward Asia crew has documented a big-scale coral bleaching from Kenting since it got warning alert level ii, which is on for the unabridged Taiwan currently from Yehliu, Longdong in the northern part to Green Island, Orchid Island, and the Pratas Islands in the southern area.

Coral Bleaching Investigation in Due south Taiwan.© Yves Chiu / Greenpeace

What are the causes of coral bleaching in Taiwan? What are the impacts? And how tin we prevent coral bleaching?

What is coral?

A lot of people may have the incorrect impression that a coral is a kind of "plant" growing in the sea. In fact, corals are actually animals with colonies of many identical individual polyps. Most of them are transparent. The riot of colors that we see comes from the algae chosen zooxanthellae that provide photosynthetic nutrients and course a symbiosis with the corals.

Taiwan used to be known every bit the coral kingdom. Although the coral reef communities widespread in Kenting, Dark-green Island, and Orchid Isle are less than one-thousandth of the globe's coral reefs in terms of scale, its various indeed is one-third of the world'due south total. 700 species of stony corals in the globe, 250 species tin can be found along the declension of Taiwan!

Red coral on Wan Li Tong reef, Green Island, Taiwan.© Paul Hilton / Greenpeace

How of import is coral to the sea?

Coral is an indispensable role of the entire marine ecosystem. Coral reefs harbor many marine creatures. All manners of creatures inhabit, brood, feed, and avert enemies in coral reefs, which naturally forms a rich ecosystem. There tin be as many as 1,500 types of fish inside coral reefs. That'due south why information technology is dubbed the "tropical rainforest in the sea."

What is coral bleaching?

Coral is the longest-lived fauna, as long as the environmental weather condition are good enough, it can abound for hundreds of years. Therefore, the death of coral colonies is usually due to the depressing living environment or the devastation of other creatures.

Corals are extremely sensitive to the surrounding. Changes in environmental conditions, such equally h2o temperatures, pH values, and turbidity volition directly affect the symbiotic relationship between corals and zooxanthellae. When the living surround is non optimal, the symbiotic zooxanthellae will gradually leave the corals or be expelled by the coral, and the corals that lose their colour sources will gradually bleach.

After the symbiotic algae leaves, the corals will non die immediately. If the environment becomes amend, the bleached corals can regain the zooxanthellae and slowly recover for survival.   However, if they bleach for a long time, the corals volition gradually weaken and die. Therefore, coral bleaching is the last distress indicate for corals.

Causes of coral bleaching: global warming and human pollution

Global warming is bad for coral reef growth

With the drastic changes of climate in recent years, global warming has caused seawater temperatures to rise, and the greenhouse effect has as well caused "ocean acidification" that weakened coral'southward absorption of calcium carbonate. When coral reefs are not potent enough to resist natural erosion it will take longer for them to recover from bleaching.

NOAA'due south coral reef observing system uses satellites to monitor the body of water surface temperature and marks areas with high water temperatures to alert the gamble of coral bleaching. Due to the Pacific high this year, Taiwan has encountered fewer typhoons that pb to higher temperatures of the land and sea. The waters around Taiwan, including Pratas Islands and Taiping Island, have recorded ocean temperatures of xxx°C.

The optimal water temperature range for coral growth is 20-28°C. If the water temperature is lower than 18°C or higher than 30°C, well-nigh corals volition expel the symbiotic algae in their body, causing bleaching or even death. If the number of typhoons in Taiwan this year is expected to stay low, the state of affairs of coral bleaching will appear pessimistic while the bounding main temperature remains high. It is worth noting that short-term changes in sea temperature will not cause bleaching. The chief crusade of large-scale coral bleaching is oft the continuous abnormal warming of the seawater.

The temperature of bounding main waters has continued to ascent since May in southern Taiwan. This is a documentation that records coral bleaching at three diving sites in Kenting in the area in August.
© Yves Chiu / Greenpeace

Human activities are a culprit

In addition, terrestrial and marine pollutants due to human activities can easily crusade harmful impacts on coral reefs, such as agricultural pesticides flowing into rivers, industrial and household wastewater discharged into the ocean, and even sunscreen products considering they contain chemicals like Benzophenone and Octyl methoxycinnamate that volition disrupt their reproduction and growth cycles.

 Marine ecosystems are hitting hard

The destruction and decease of coral reefs has dealt a major blow to the marine ecosystem. In fact, the growth charge per unit of corals is very slow. They only grow about ane centimeter a year. Therefore, the coral reefs we come across in the ocean are often the results of decades or even centuries.  Once they're damaged, they'll need the aforementioned amount of time to resume their original size.

In addition to conserving diverse marine life, a salubrious coral reef ecosystem besides supports various human being needs. It not only protects the adjacent coastline from bounding main erosion merely besides has loftier economic values. It can generate billions of dollars in tourism revenue. Therefore, the decline of the ecosystem caused by coral bleaching will inevitably affect the livelihoods of industries that depend on coral reefs, such every bit tourism and fishery.

How to solve the trouble of coral bleaching?

Energy-saving and carbon reduction to slow down global warming

 In the face of the unusual increment in seawater temperature caused by climatic change, more ambitious carbon reduction targets should be prepare to replace fossil fuels with sustainable energy.

Everyone can save the coral

Cute corals provide habitat for diversified marine creatures. Even so, various man activities, excessive coastal development, or the unusual increase in seawater temperatures due to climate change have put bang-up pressure on corals. As human being beings become to know the importance of coral reefs, the related preservation piece of work tin exist started on the individual level.

Healthy Corals and Oceans are important to the Globe and humankind. © Paul Hilton / Greenpeace

"Coral is an indispensable part in the oceans, as it formed a convoluted ecological cycle for other species, such as a resting and reproducing area, also as the food-finding place and fugitive dangers," said Lena Chang, climate and energy campaigner at Greenpeace East asia. "Information technology'southward dubbed the rainforest in the oceans because it tin harbor upwardly to ane,500 types of fish."

"A healthy coral reef can bring upon high economic values," said Chang. "It's an nugget to generate billions of dollars in revenues from tourism. And information technology protects the coastline from oceans weathering. If the unabridged environmental is damaged, the tourism and fishery industries will be obviously affected as well."

Greenpeace East asia urged policymakers to declare a climate emergency, putting climate-related risk disclosure and carbon reduction targets on the agenda in accordance with the Paris Understanding.