Human Impacts on Coral Reefs

Human Impacts on Coral Reefs

Part 1Natural Stresses and Human Uses

Part 1Natural Stresses and Human Uses

Factors Correlated with Healthy Coral Reef Growth

Factors Correlated with Healthy Coral Reef Growth

• water temperature range: 18 – 29C• normal seawater salinity: 32 – 35 ‰

• low inorganic nutrient concentrations (oligotrophic waters)

• clear, transparent water

• little or no sedimentation

• vigorous water motion

• water temperature range: 18 – 29C• normal seawater salinity: 32 – 35 ‰

• low inorganic nutrient concentrations (oligotrophic waters)

• clear, transparent water

• little or no sedimentation

• vigorous water motion

Natural Sources of Stress on Coral Reefs

Natural Sources of Stress on Coral Reefs

• intense storms

• El Niño

• disease

• volcanic eruptions

• predator population explosions

• natural stream and river runoff

• exceptionally low tides

• intense storms

• El Niño

• disease

• volcanic eruptions

• predator population explosions

• natural stream and river runoff

• exceptionally low tides

Storm Wave DamageStorm Wave Damage

BeforeBefore AfterAfter

Storm DamageStorm Damage

Normal Wind and Ocean Circulation in the PacificNormal Wind and Ocean Circulation in the Pacific

El Niño ConditionsEl Niño Conditions

Sea Surface Temperatures

April 8, 2013

Impacts of El NiñoImpacts of El Niño

Marine Life Impacted

Drought

Floods Tropical Storm

Forest Fires Bird life impacted

Coral Reef Damage Coastal Erosion

DiseaseDisease

Lava FlowsLava Flows

Crown-of-Thorns OutbreaksCrown-of-Thorns Outbreaks

Stream and River RunoffStream and River Runoff

Low TidesLow Tides

Some Local Human ImpactsSome Local Human Impacts

• thermal effluents

• sewage discharges and agricultural runoff

• mechanical damage to reefs

• sedimentation

• destructive resource extraction practices

• introduced species

• loving a reef to death

• thermal effluents

• sewage discharges and agricultural runoff

• mechanical damage to reefs

• sedimentation

• destructive resource extraction practices

• introduced species

• loving a reef to death

Global Human ImpactsGlobal Human Impacts

• global warming• ozone depletion• ocean acidification

• global warming• ozone depletion• ocean acidification

Possible Consequences of Stresses and Impacts on Corals and Coral Reefs

Possible Consequences of Stresses and Impacts on Corals and Coral Reefs

• outright mortality of coral tissues

• breakage of coral colonies

• bleaching

• diseases

• slower growth

• reduced reproduction and recruitment

• competitive exclusion by other organisms

• increased reef erosion

• outright mortality of coral tissues

• breakage of coral colonies

• bleaching

• diseases

• slower growth

• reduced reproduction and recruitment

• competitive exclusion by other organisms

• increased reef erosion

Traditional Hawaiian Uses of Coral Reef ResourcesTraditional Hawaiian Uses of Coral Reef Resources

Seaweedslimu

Seaweedslimu

Hooks andLures

Hooks andLures

Octopus Lure

Fishing Shrinesko‘a

Fishing Shrinesko‘a

Hawaiian Fish PondsHawaiian Fish Ponds

He'eia fishpond

Ahupua’a

1. Upland2. Plains3. Ocean

Ranges from the tip of the mtn to the reef area

TheAhupua‘a

TheAhupua‘a

Modern Uses of Coral ReefsModern Uses of Coral Reefs• Seafood• Food Additives and Toiletries• Health and Medicine Products• Research and Education• Jewelry and Art• Marine Aquarium Specimens• New Land• Cement & Other Building Supplies• Shoreline Protection• Recreation

• Seafood• Food Additives and Toiletries• Health and Medicine Products• Research and Education• Jewelry and Art• Marine Aquarium Specimens• New Land• Cement & Other Building Supplies• Shoreline Protection• Recreation