34
2 Coral Reef Ecosystem
deforestation, agricultural pollution, dredging and mining operations contribute to
the worsening quality of reef waters (Biscéré et al. 2018). It is remarkable to mention
that numerous of the ecological changes in coral reefs could be traced back to anthropological activities that began centuries ago with recent rates of change escalating
and leading to unprecedented loses of ecosystem services (Hoegh-Guldberg et al.
2019).
2.5.2.1 Local Disturbances
Local disturbances include destructive fishing with dynamite or cyanide; unsustainable tourism; pollution related to fertilizers and pesticides from agriculture and the
evacuation of wastewater; sedimentation; proliferation of Acanthaster starfish; and
the use of coral skeletons as a building material (Burke et al. 2011); overexploitation of marine resources; careless anchoring of boats (Hoegh-Guldberg et al. 2011);
recreational damage; and excess access to corals for research purposes.
Coral reefs are increasingly exposed to growing loads of nutrients, sediments,
pollutants discharged from land (Fabricius 2005) and metal contamination (Marques
et al. 2019). Such disturbances can result in significant loss of ecosystem services
impacting on social, cultural, biological and economic values (Bainbridge et al.
2018). Anthropogenic inputs can cause changes to the water quality and thus disrupt
key chemical interactions among reef organisms (Peters et al. 1997; Bielmyer et al.
2010).
Anthropogenically induced stress to coral reefs is mainly associated with high
population densities in coastal areas and the combined exposure of multiple interacting stressors (Bielmyer-Fraser et al. 2018; Maximillian et al. 2019). The expansion
of human population in coastal areas and the accompanying urbanization and agricultural activities have increased the discharge of industrial wastes and untreated
sewages into adjacent coral reefs (Hédouin et al. 2011) and these are escalating at
an alarming rate.
The presence of humans within the proximity of coral reefs usually results in
an elevated input of nutrients into reef waters (D’Angelo and Wiedenmann 2014).
Municipal and industrial effluents add nitrogen, phosphorous, and industrial chemicals to the coastal environment, leading to eutrophication that produces a degradation
of the marine food web (Maximillian et al. 2019); and at the same time leading to
a reduction in the amount of light reaching the zooxanthellae and hence reduces
photosynthesis, which in turn slows the coral growth and this may eventually lead to
its death.
Activities such as coastal construction of breakwaters and marinas; land reclamation; beach nourishment; construction of ports and aquaculture facilities are carried
out to meet the growing economic and societal demands in the coastal zone worldwide (Erftemeijer et al. 2012; Maximillian et al. 2019). Infrastructural and extension
of agricultural developments to marginal lands have often led to increased turbidity
and sedimentation in the surrounding coastal areas.
2 Coral Reef Ecosystem
deforestation, agricultural pollution, dredging and mining operations contribute to
the worsening quality of reef waters (Biscéré et al. 2018). It is remarkable to mention
that numerous of the ecological changes in coral reefs could be traced back to anthropological activities that began centuries ago with recent rates of change escalating
and leading to unprecedented loses of ecosystem services (Hoegh-Guldberg et al.
2019).
2.5.2.1 Local Disturbances
Local disturbances include destructive fishing with dynamite or cyanide; unsustainable tourism; pollution related to fertilizers and pesticides from agriculture and the
evacuation of wastewater; sedimentation; proliferation of Acanthaster starfish; and
the use of coral skeletons as a building material (Burke et al. 2011); overexploitation of marine resources; careless anchoring of boats (Hoegh-Guldberg et al. 2011);
recreational damage; and excess access to corals for research purposes.
Coral reefs are increasingly exposed to growing loads of nutrients, sediments,
pollutants discharged from land (Fabricius 2005) and metal contamination (Marques
et al. 2019). Such disturbances can result in significant loss of ecosystem services
impacting on social, cultural, biological and economic values (Bainbridge et al.
2018). Anthropogenic inputs can cause changes to the water quality and thus disrupt
key chemical interactions among reef organisms (Peters et al. 1997; Bielmyer et al.
2010).
Anthropogenically induced stress to coral reefs is mainly associated with high
population densities in coastal areas and the combined exposure of multiple interacting stressors (Bielmyer-Fraser et al. 2018; Maximillian et al. 2019). The expansion
of human population in coastal areas and the accompanying urbanization and agricultural activities have increased the discharge of industrial wastes and untreated
sewages into adjacent coral reefs (Hédouin et al. 2011) and these are escalating at
an alarming rate.
The presence of humans within the proximity of coral reefs usually results in
an elevated input of nutrients into reef waters (D’Angelo and Wiedenmann 2014).
Municipal and industrial effluents add nitrogen, phosphorous, and industrial chemicals to the coastal environment, leading to eutrophication that produces a degradation
of the marine food web (Maximillian et al. 2019); and at the same time leading to
a reduction in the amount of light reaching the zooxanthellae and hence reduces
photosynthesis, which in turn slows the coral growth and this may eventually lead to
its death.
Activities such as coastal construction of breakwaters and marinas; land reclamation; beach nourishment; construction of ports and aquaculture facilities are carried
out to meet the growing economic and societal demands in the coastal zone worldwide (Erftemeijer et al. 2012; Maximillian et al. 2019). Infrastructural and extension
of agricultural developments to marginal lands have often led to increased turbidity
and sedimentation in the surrounding coastal areas.