Face Elevated Extinction Risk from Climate Change

Introduction

Coral reef is a rock structure, comprising of a series of calcareous skeleton of marine organism carriers. The limestone composition of the coral reef is quite resistant to the action of waves and tides, and it is also rigid. However, the reefs may grow fragile due to changes in the ecosystem. It is estimated that 27% of the entire world’s coral reefs have already been degraded irreversibly by global warming and predatory actions such as irregular growth of coastal cities and human pollution (Bozec, Alvarez-Filip, & Mumby, 2015).

The reefs occur in coastal locations containing clear, shallow and warm waters. These reefs are extremely important to many people who depend on them for fishing, tourism and other economic activities. The environmental importance of coral reefs is mainly attributed to the fact that marine ecosystems have a broad biodiversity with numerous fish, crustaceans and other aquatic animals that depend directly or indirectly on the formations, besides offering protection to coastal systems as a natural barrier to the tides (Wolff et al., 2015).

Coral reefs are ancient formations made of calcium carbonate and usually produced by small soft-bodied animals called “polyps” (they may be less than one centimeter in diameter). Polyps  build some type of limestone shell where lodges form along with billions of polyps called colonies that normally constitute the limestone reef structure. Along with polyp, a tiny alga called “zooxanthelae” terminates its life by giving the typical characteristic of coral colors such as green, blue, yellow, lilac, and among others (Lane et al. 2013).

An extremely important association for coral-reefs is the symbiosis that occurs between species of coral and microalgae known as zooxanthellae. These algae live inside the tissues of coral reef builders and perform photosynthesis by releasing nutritious organic compounds referred to as corals. In return, zooxanthellate survives and grows using the products generated by coral metabolism such as carbon dioxide, nitrogen and phosphorus compounds. They are also involved in the secretion of calcium and formation of the coral skeleton. Although coral species are found in almost all oceans and altitudes, the species known as reef builders (hermatypic corals) are restricted in tropical and subtropical regions. The reefs generally require warm aquatic environment (25^o-30^oC) and clear freshwater surrounding (Weijerman et al., 2015).

Pollution (domestic sewage, oil spills, etc.) and sedimentation (sediments brought into the sea due to deforestation and earthworks) put at risk many coral reefs, including other numerous organisms that depend on them (such as human communities who rely on fishing and collecting marine reef animals). Apparently, new phenomenon that has not been fully understood by researchers has occurred in all regions that host coral reefs. The phenomenon is referred to as bleaching. It refers to basic loss of plant organisms (zooxanthellae) that are present in coral tissues. Zooxanthellae also occur in other cnidarians such as Anemones Sea, zooantídeos, jellyfish and other invertebrates like sea squirts, sponges, mollusks among others. Most coral tissues become nearly transparent when exposed to the bleaching effect. Hence, the pollution process leads to exposure of the underlying white skeleton. Marine Scientists argue that the effects brought about by climate change and global warming have massively contributed towards gradual loss of coral reefs.

It is estimated that coral reefs cover about 284,300 km². The region of the Indo-Pacific (Southeast Asia, Indian Ocean, Pacific Ocean and the Red Sea) contributing 91.9% of the total, while the reefs of the Atlantic Ocean and the Caribbean Sea contribute only 7.6%. The Northeast region of Brazil is the only South Atlantic Ocean region with reef formations that are distributed throughout the coast of the Northeast.  This paper offers a succinct discussion on how the reef-building corals face elevated extinction risk from climate change.

Structural causes

According to the Stern Report (a leaked document in October 2006 by the chief economist of the British Government), a temperature rise of about 3° C can cause drought in Europe and general lack of water to four billion people. It may also cause millions of new cases of malnutrition. Other verified facts on climate change include:

Elevation of 1° C in global temperature may lead to shrinking of glaciers and threaten water supply for 50 million people and a marginal increase in cereal production in temperate regions (Weijerman et al., 2015). Worse still, at least 300,000 people die every year because of malaria, malnutrition and other diseases related to climate change. A decrease in mortality rate during winter in regions of higher latitude can also take place coupled with the death of 80% of coral reefs especially the Great Barrier Reef.

Elevation of 2º C in global temperature may leads to a 5% to 10% decrease in cereal production in tropical Africa. About 40 to 60 million more people may be exposed to malaria in Africa and up to 10 million more people may be endangered by flooding in coastal regions. On the same note, between 15% and 40% of living species may find themselves threatened with extinction (Thorner, Kumar, & Smith, 2014). There is great risk of extinction of species in the Arctic. A case in point is the polar bears. It is highly likely that the ice sheet of Greenland may begin to melt down and the process cannot be reversed in the future.  As a result, sea level is expected to go up significantly.

A 3° C rise in global temperature is even more harmful to the wellbeing and existence of coral reefs. In southern Europe, drought may be pronounced every ten years. Between 1 and 4 billion more people are facing periods of water shortage while 150 to 550 million more people are being exposed to the threat of hunger. 1 to 3 million more people die from malnutrition and there is possible beginning of the collapse of the Amazon rainforest; raising the risk of collapse of the Ice Sheet of West Antarctica (Santos et al., 2014). We are also facing the risk of collapse of the warm waters of the Atlantic circulation system. When all these changes take place due to changes in climate, coral reefs are also affected either directly or indirectly.

Coral reefs are vulnerable to current climate change and further to that, the challenge can be projected into the future especially when it comes to rapid and extreme climatic shifts.

The most vulnerable areas include the Amazon and Northeast Brazil as shown in recent studies. Knowledge of possible climatic-hydrologic scenarios and its uncertainties can help estimate water demands in the future and define environmental policies of use and water management.

Economic components

Researchers assess the health of coral species around the world by measuring the decrease in abundance on reefs and ocean floors where they settle and then use the criteria developed by the World Conservation Union (IUCN) to determine the risk of extinction. Past experiments realized gross declines of up to 80 percent in the quantity of corals residing in some locations.

Corals are the mainstay of the ecosystem. Marine scientists are worried about what will occur to the large biodiversity system that relies on corals if significant drop of biodiversity continue to happen in the coming decades.

A similar check took place on the health of coral formed in American water. Form the research report; about half of all the coral species in these waters are trying to survive even though they are declining considerably.

The formation of coral reefs is anticipated to go down within the next five to ten decades due to gradual disappearance of vital sea species that form corals. This experiment results were released based on the Decree of threatened Species. The latter implies that within a period of three decades or so, some crucial reefs such as those located in the Caribbean Sea may cease to exist. Measures to control this risk and preserve the two species are almost being concluded.

On the other hand, some marine scientists have a different opinion regarding coral reefs being at risk. They argue that climate change on its own is not capable of eliminating the existence of coral reefs on this planet since aquatic animals will always be there to ensure continual formation of reefs. The ecological function of many coral reef builders is threatened by very minimal losses of their abundance.

The best way to safeguard coral reefs is to improve the general ecosystem management of ocean waters. In other words, the effects of climate change are far-reaching and unless broad preservation measures are put in place, the reefs will continue to disappear with the passaging of time. This would also maximize the number of species that depend on them for food or habitat. As a matter of fact, climate change and variability may pose significant alterations to the natural ecosystem of aquatic life. Some plant and animal species can hardly survive in certain temperature regimes even though they are required in the vast formation of coral reefs.

Ideological components

Coral reefs are considered one of the oldest and richest ecosystems on Earth. Thus, their ecological, social and economic importance is indisputable. The reef environments are considered, along with tropical forests, one of the most diverse planet’s natural communities. This enormous diversity of life can be measured bearing in mind that one in four marine species lives in coral reefs, including 65% of fish species. They are marine ecosystems found in regions of warm and clear waters and formed by the deposition of calcareous skeleton organisms like corals, algae and mollusks. They are important habitats for fish and other fisheries such as lobster, crab and oyster. They also provide support and shelter to endangered species like the sea turtle and manatee.

The word ‘reef’ refers to a rock or series of cliffs located near the coast or directly linked, submerged or slightly above the sea level. Reefs can be made up of sandstone that results from the consolidation of ancient beaches or coralline formations or accumulation of shells of certain marine animals. A coral reef is a rocky, rigid structure that resists mechanical action of waves and currents and is built by marine organisms (dead animals and plants).

As much as the coral reefs might be rigid sea structures, climate change can significantly affect their firmness through massive and destructive sea waves and tides. A typical example of such waves is tsunami. The latter has been witnessed in recent years. This weather event is capable of shaking and ruining coral reef formations. While weather is considered a natural event, it is vital to mention that human activities are capable of altering weather patterns and hence climatic features of a region or the whole globe. As the global temperatures continue to rise, leading to higher rates of evaporation, both aquatic and terrestrial environments are expected to continue receiving massive downpour coupled with erratic weather. As a result, the structural formations of coral reefs grow weak; they are worn out and may eventually go extinct.

Corals are often confused with stones or plants, since they are structurally formed by a thick layer of dead calcareous material with a thin layer of living tissue on their surface. When we talk about corals, we are basically referring to the dead animals and skeletons that were left. This implies that the structural formation of coral reefs wholly depends on marine plants and animals (Chollett, Enríquez, & Mumby, 2014). Climate change is bound to negatively affect aquatic life and consequently, some animal and plant species may disappear with the passage of time. For instance, some marine organisms cannot thrive in elevated temperatures. Therefore, the rising global temperatures (global warming) may reduce their lifespan and even eliminate their existence completely.

Social/cultural practices

The social aspects of tourism may affect the coral reef ecosystem both negatively and positively. For example, large inflow of visitors to coral sites may lead to direct physical damage to the reefs. Human activities such as boating, diving and snorkeling can hardly spare reefs especially when tourists flock such sites. The reefs may also be over-exploited through collecting and fishing. Reef species that have already been endangered can further be threatened when all the aforementioned human activities are directed towards them.

When facilities such as airports, sea ports, marinas and resorts are constructed near the establishment of coral reefs, the system is bound to be indirectly exposed to numerous threats and risks such as poor waste disposal that finds its way to the water channels, flow of toxic effluents from resorts to reef sites as well as air and water pollution from the immediate surroundings (Ban, Pressey, & Graham, 2015).

When snorkelers and divers overuse the coral establishment area, reef degradation is hastened. Boat groundings and anchors are particular very harmful to the growth and sustenance of the reefs. When large boats are sailed and anchored near the coral reefs, the damage is even severe.

Human beings will also suffer the consequences of coral bleaching process. Tourism on the Great Barrier generates at least $ 5 billion a year and employs about 70,000 people

According to estimates, half a billion people worldwide benefit from productivity and protection of coral reefs based on figures obtained from the National Oceanic and Atmospheric Administration (Magris, Heron, & Pressey, 2015). In addition, human dwellings rely on coral reefs for protection against strong tides and waves that emanate from deep seas and oceans. Without the reefs, there would be erosion of the shore which may be followed by disappearance of coastal cities.

Conclusion

There is clear and certain picture of the possible climate change impacts on spatial and temporal distribution of water resources across the globe. Any structural or capacity adjustment to water bodies is capable of interfering with the formation, structure and lifespan of reefs. Uncertainties still represent obstacles for operational planning and management of water resources and marine life.

One of the immediate actions would be to establish research and monitoring programs to assess the risks related to climate change and in particular, how the coral reefs can be sustained without them going into extinction. Regions such as the Northeast and West-East of South America are highly vulnerable due to overdependence on natural water resources. In these regions, climate changes (especially in the form of air temperature increase) can add the risk posed by the growing population, industrialization and changes in land use associated with agriculture and livestock. In the Amazon, the problems are associated with a possible loss of biodiversity and impacts to the hydrological cycle in the long term. These effects may increase the risk of extreme rainfall as a result of changes in atmospheric moisture.

Scientific evidence points to the fact that climate change poses a serious threat to water resources globally. Not only future climate changes pose a risk, but climate variability as well. Some regions have gone through the worst drought episodes. The impacts of climate variations and changes can be worsened by other non-environmental factors such as political and social aspects.

Changes in land use continue to be the main short-term threat to the survival of coral reefs while climate change and the associated interactions become increasingly important. In addition, historic and habitat loss will continue to occur throughout the 21^st century. In turn, temperate forests will disappear in the southern part and low latitude areas.

Demand for seafood continues to grow due to the increasing population. Fish stocks are currently highly endangered due to massive invasion of their living environment. The growing trends of the extension of fishing operation to the entire marine food chain and the top predators for the other tropic levels occur at the expense of marine biodiversity (continuous decline in the Marine Tropic Index in many areas). Climate changes often compel several aquatic animals to migrate in colder regions so that they contain the increasing environmental temperature. Since these animals are needed in the development of coral reefs, it is apparent that reefs may no longer be formed in certain ocean zones due to the absence of aquatic life. Ocean acidification weakens the ability of mollusks, crustaceans, marine corals and phytoplankton to form their skeletons thereby threatening to destroy the marine food chain as well as reef structures. The rising rate of effluents that finally find their way to costal belts is a major source of pollution and long term destruction to reefs. Unless mitigation measures are put in place, the coral reefs may eventually disappear.

It is evident that the impacts of climate are grossly harmful to the growth, development and long-term sustenance of coral reefs. Unless drastic measures are put in place to reverse the effects of climate variability and change, the coral reef system may become extinct in future.