Human impacts on coral include:
Coral reefs are threatened by human activities throughout the world. In southeast Asia, the hot
spot of coral diversity, more than 80% of the reefs are at risk from coastal development and
harmful fishing practices.
Macro algae
Pollution
Population growth and development threaten the survival of coral reefs
Population growth and urban development currently rank among the greatest threats to coral
reefs. Development activities cause erosion, resulting in the run-off of sediments which
eventually reaching the reefs. Also storm water runoff carries fertilizers and sewage into the
ocean, damaging coral reefs. Increase of nutrient concentrations within the reef environment is
followed by increase of algae, which may smother corals. Whether it is from direct
sedimentation or an increase in turbidity from nutrient-loading, the amount of sunlight reaching
the corals is reduced.
Shrimp boats
Overfishing
Over fishing has altered ecological dynamics of marine communities
Along with human population growth, the harvest of resources from the sea is ever-increasing.
Overfishing has changed the ecological dynamics of marine communities, allowing some
organisms to dominate reefs that once were kept in check by large reef fish populations.
Fishing practices have also become more destructive as fish populations decrease. In some
regions, indiscriminate fish traps are used while in other areas the use of dynamite and cyanide
have become common practice.
Tourism
Increase in tourism is responsible for increase in reef damage.
Coral reefs attract ecotourists, bringing much needed currency to tropical regions. Ironically, the
increase in ecotourism is usually accompanied by an increase in reef damage. Divers and
snorkelers may harm the corals by touching the polyps, while the boats transporting ecotourists
to the reef may damage the reef by dragging anchors. Although ecotourism is responsible for
reef damage, if it is carefully managed and monitored, ecotourism may actually help preserve
these valuable habitats.
Aquarium and Souvenir Trade
Fish and invertebrates are harvested from the world's coral reefs.
Many species of fish and invertebrates are harvested from the world's coral reefs for the
aquarium industry. Unfortunately, poisons such as cyanide are often used in the Indo-Pacific
region, causing the deaths of many fish and surrounding corals. After the live fish are collected,
up to half die as a result of poisoning or stress. Those that do survive have high mortality rates
in home aquariams due to dietary and physical requirements. Corals and shells are also
collected throughout the world and sold as souvenirs to tourists, made into jewelry, or exported
as curios.
Climate Change Research - Data Collection
Global Climate Change
Rising sea temperatures cause coral bleaching
Global climate change may cause increases in sea temperature and sea level as well as ocean
current patterns, all of which can cause damage to reefs. Corals are very sensitive to water
temperature changes, with rises in temperature resulting in coral bleaching episodes.
- Pollution
- Overfishing
- Tourism
- Aquarium/Souvenir Trade
- Global Climate Change
Coral reefs are threatened by human activities throughout the world. In southeast Asia, the hot
spot of coral diversity, more than 80% of the reefs are at risk from coastal development and
harmful fishing practices.
Macro algae
Pollution
Population growth and development threaten the survival of coral reefs
Population growth and urban development currently rank among the greatest threats to coral
reefs. Development activities cause erosion, resulting in the run-off of sediments which
eventually reaching the reefs. Also storm water runoff carries fertilizers and sewage into the
ocean, damaging coral reefs. Increase of nutrient concentrations within the reef environment is
followed by increase of algae, which may smother corals. Whether it is from direct
sedimentation or an increase in turbidity from nutrient-loading, the amount of sunlight reaching
the corals is reduced.
Shrimp boats
Overfishing
Over fishing has altered ecological dynamics of marine communities
Along with human population growth, the harvest of resources from the sea is ever-increasing.
Overfishing has changed the ecological dynamics of marine communities, allowing some
organisms to dominate reefs that once were kept in check by large reef fish populations.
Fishing practices have also become more destructive as fish populations decrease. In some
regions, indiscriminate fish traps are used while in other areas the use of dynamite and cyanide
have become common practice.
Tourism
Increase in tourism is responsible for increase in reef damage.
Coral reefs attract ecotourists, bringing much needed currency to tropical regions. Ironically, the
increase in ecotourism is usually accompanied by an increase in reef damage. Divers and
snorkelers may harm the corals by touching the polyps, while the boats transporting ecotourists
to the reef may damage the reef by dragging anchors. Although ecotourism is responsible for
reef damage, if it is carefully managed and monitored, ecotourism may actually help preserve
these valuable habitats.
Aquarium and Souvenir Trade
Fish and invertebrates are harvested from the world's coral reefs.
Many species of fish and invertebrates are harvested from the world's coral reefs for the
aquarium industry. Unfortunately, poisons such as cyanide are often used in the Indo-Pacific
region, causing the deaths of many fish and surrounding corals. After the live fish are collected,
up to half die as a result of poisoning or stress. Those that do survive have high mortality rates
in home aquariams due to dietary and physical requirements. Corals and shells are also
collected throughout the world and sold as souvenirs to tourists, made into jewelry, or exported
as curios.
Climate Change Research - Data Collection
Global Climate Change
Rising sea temperatures cause coral bleaching
Global climate change may cause increases in sea temperature and sea level as well as ocean
current patterns, all of which can cause damage to reefs. Corals are very sensitive to water
temperature changes, with rises in temperature resulting in coral bleaching episodes.
Natural impacts on corals include:
Storms
Storms and hurricanes may cause extensive damage to reef structures and communities.
Although much of coral reef destruction is blamed on human activity, natural disturbances are
also capable of causing extensive damage to coral reefs. Strong waves caused by storms and
hurricanes may smash into the reef, breaking up large corals and creating rubble fields. Storms
also harm reefs indirectly by disrupting near shore habitats, resulting in the release of large
amounts of sediments and freshwater to come into contact with the reef. These disturbances
open spaces for new organisms to colonize, preserving overall biodiversity.
Thermal Stress
Thermal stress can induce the loss of symbiotic algae from corals, often referred to as "coral
bleaching". Heat-related stress often occurs during late summer months when the sun is
intense. Corals can survive water temperatures as high as 86-95°F (30-35°C), depending upon
the species. Increases in water temperature often causes loss of symbiotic algae from coral
tissues, referred to as coral bleaching. Corals are also susceptible to cold stress at
temperatures at or below 57°F (14°C). Cold water masses originate in Florida Bay, causing
coral death in patch reefs long the water current's path. However, most offshore corals
experience little damage due to the mixing of the cold water current with the warm offshore
waters, moderating temperatures and lessening the impact on surrounding reefs.
Diseases
Coral reef organisms, such as the long-spined sea urchin, are susceptible to many
pathogens. Along with coral bleaching, black band disease, and white band disease, coral reef
organisms are subject to many pathogens. During the 1980s, a water-borne pathogen caused
the massive die off of the long-spined sea urchin, Diadema antillarum. Long-spined sea urchin
populations were reduced as much as 95% in some locations. This urchin is an important
herbivore, keeping algae growth in control in reef habitats. The decline in sea urchin
populations resulted in algal overgrowth throughout the reefs of the Caribbean.
- Storms
- Thermal Stress
- Diseases
Storms
Storms and hurricanes may cause extensive damage to reef structures and communities.
Although much of coral reef destruction is blamed on human activity, natural disturbances are
also capable of causing extensive damage to coral reefs. Strong waves caused by storms and
hurricanes may smash into the reef, breaking up large corals and creating rubble fields. Storms
also harm reefs indirectly by disrupting near shore habitats, resulting in the release of large
amounts of sediments and freshwater to come into contact with the reef. These disturbances
open spaces for new organisms to colonize, preserving overall biodiversity.
Thermal Stress
Thermal stress can induce the loss of symbiotic algae from corals, often referred to as "coral
bleaching". Heat-related stress often occurs during late summer months when the sun is
intense. Corals can survive water temperatures as high as 86-95°F (30-35°C), depending upon
the species. Increases in water temperature often causes loss of symbiotic algae from coral
tissues, referred to as coral bleaching. Corals are also susceptible to cold stress at
temperatures at or below 57°F (14°C). Cold water masses originate in Florida Bay, causing
coral death in patch reefs long the water current's path. However, most offshore corals
experience little damage due to the mixing of the cold water current with the warm offshore
waters, moderating temperatures and lessening the impact on surrounding reefs.
Diseases
Coral reef organisms, such as the long-spined sea urchin, are susceptible to many
pathogens. Along with coral bleaching, black band disease, and white band disease, coral reef
organisms are subject to many pathogens. During the 1980s, a water-borne pathogen caused
the massive die off of the long-spined sea urchin, Diadema antillarum. Long-spined sea urchin
populations were reduced as much as 95% in some locations. This urchin is an important
herbivore, keeping algae growth in control in reef habitats. The decline in sea urchin
populations resulted in algal overgrowth throughout the reefs of the Caribbean.
Natural Threats to Coral Reefs
Impacts & Threats to Coral Reefs
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