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2 Coral Reef Ecosystem
Unique compounds obtained from coral reefs have helped in the treatment of
cardiovascular diseases, ulcers, leukemia, and skin cancer and in the treatment for
people infected with HIV (UNEP 2005). Corals possess anticarcinogenic properties (Ruiz-Torres et al. 2017) and anti-inflammatory, anti-cancer and anti-oxidant
activities (Wei et al. 2013).
2.5 Threats to Coral Reefs
Coral reefs are the most biodiverse and delicate ecosystems on the planet, yet are the
most susceptible to stress. The stressors could be acute or chronic, direct or indirect,
and natural or anthropogenic. Highlighted below are some common threats, which
cause coral reef degradation globally.
2.5.1 Natural Causes of Coral Reef Degradation
Local as well as global factors induce coral reef degradation naturally. Some examples include natural disasters (e.g. hurricanes/tropical storms/typhoons, earthquakes)
(Rogers 1993; El-Naggar 2020); El Nino Southern Oscillation (ENSO) events and
global warming (leading to bleaching events); coral diseases and crown of-thorns
(COTS) starfish outbreaks (El-Naggar 2020); tidal fluctuations (Fadlallah et al. 1995);
and high/low temperature extremes, freshwater plumes after heavy downpour and
runoff events (McCulloch et al. 2003).
Tropical storms, typhoons or hurricanes do a great deal of damage such as breaking
corals by strong wave action. Though massive, the damage tends to be localized
and restricted to a particular area only (Souter and Lindén 2000). Stronger storms
enhance the intensity of floods (Anthony 2016) which lead to sedimentation issues
in the marine environment. Sedimentation causes turbid environments on the coral
reef ecosystems. The intensity and frequency of tropical cyclones is more severe and
enhanced for small island countries.
The corallivorous starfish, COTS (Acanthaster planci) become a common natural
threat to corals when they occur in elevated numbers as they generally feed on coral
tissue, thus damaging hard cover corals (Souter and Lindén 2000). If the damage
is not severe, then recovery of the coral reef from the outbreaks of COTS may
take 20–40 years (El-Naggar 2020). Acanthaster planci can produce many million
babies during 1 year, however, with an increase in the nutrients from sewage and
overharvesting of its predator, its population can escalate (El-Naggar 2020).
Acanthaster Planci greatly reduces coral cover and feeds preferentially on several
coral species, which are highly susceptible to bleaching (Baker et al. 2008).
Furthermore, white and black band disease as well as bioeroders leads to the
degradation of coral reef ecosystems to some extent. When under stress, coral reefs
suffer many bacterial infections. This is due to production of protective mucus,
2 Coral Reef Ecosystem
Unique compounds obtained from coral reefs have helped in the treatment of
cardiovascular diseases, ulcers, leukemia, and skin cancer and in the treatment for
people infected with HIV (UNEP 2005). Corals possess anticarcinogenic properties (Ruiz-Torres et al. 2017) and anti-inflammatory, anti-cancer and anti-oxidant
activities (Wei et al. 2013).
2.5 Threats to Coral Reefs
Coral reefs are the most biodiverse and delicate ecosystems on the planet, yet are the
most susceptible to stress. The stressors could be acute or chronic, direct or indirect,
and natural or anthropogenic. Highlighted below are some common threats, which
cause coral reef degradation globally.
2.5.1 Natural Causes of Coral Reef Degradation
Local as well as global factors induce coral reef degradation naturally. Some examples include natural disasters (e.g. hurricanes/tropical storms/typhoons, earthquakes)
(Rogers 1993; El-Naggar 2020); El Nino Southern Oscillation (ENSO) events and
global warming (leading to bleaching events); coral diseases and crown of-thorns
(COTS) starfish outbreaks (El-Naggar 2020); tidal fluctuations (Fadlallah et al. 1995);
and high/low temperature extremes, freshwater plumes after heavy downpour and
runoff events (McCulloch et al. 2003).
Tropical storms, typhoons or hurricanes do a great deal of damage such as breaking
corals by strong wave action. Though massive, the damage tends to be localized
and restricted to a particular area only (Souter and Lindén 2000). Stronger storms
enhance the intensity of floods (Anthony 2016) which lead to sedimentation issues
in the marine environment. Sedimentation causes turbid environments on the coral
reef ecosystems. The intensity and frequency of tropical cyclones is more severe and
enhanced for small island countries.
The corallivorous starfish, COTS (Acanthaster planci) become a common natural
threat to corals when they occur in elevated numbers as they generally feed on coral
tissue, thus damaging hard cover corals (Souter and Lindén 2000). If the damage
is not severe, then recovery of the coral reef from the outbreaks of COTS may
take 20–40 years (El-Naggar 2020). Acanthaster planci can produce many million
babies during 1 year, however, with an increase in the nutrients from sewage and
overharvesting of its predator, its population can escalate (El-Naggar 2020).
Acanthaster Planci greatly reduces coral cover and feeds preferentially on several
coral species, which are highly susceptible to bleaching (Baker et al. 2008).
Furthermore, white and black band disease as well as bioeroders leads to the
degradation of coral reef ecosystems to some extent. When under stress, coral reefs
suffer many bacterial infections. This is due to production of protective mucus,