Selected Habitat: Tropical Coral Reefs Flashcards
What group do corals belong to?
Phylum Cnidaria
How many species are in the group phylum cnidaria?
10,000
What are cilia?
Finger like projections on a coral polyp which trap plantonic items floating past and pass it to the stomach
What is nematocyst?
These are stinging cells that harpoon Plantonic organisms floating past a polyp
What is the name of the Symbiotic algae on coral
Zooxanthellae – Photosynthetic algae
How do zooxanthellae help coral?
Absorbs sunlight invite food energy for themselves and the coral polyps
Why is it a symbiotic relationship between the polyps and the algae
Waste products produced by the polyps is directly absorbed by the algae for photosynthesis and growth
Algae produce oxygen and glucose which the coral polyps need
What percentage of the corals food energy comes from the algae
95% of the energy from the symbiotic relationship
What do the algae get in return from the coral
Protected habitat and supply of nutrients
What is the carbon from the coral used for?
Either used by the algae or used to make calcium carbonate which is the corals protective shell
What are reef building corals?
Many species of corals secrete a limestone base which is continually added to, building up into a reef
Why are tropical coral reefs vulnerable to climate change?
As they have very specific abiotic conditions
What are the light needs of coral?
The symbiotic algae require bright sunlight, in the tropics there is bright sunlight in shallow water for about 12 hours every day
What temperature range is needed for coral survival
Warm and constant in the range of 25–29°C
What is immersion
Polyps must be covered in water almost all the time to prevent them from drying out
Why Can’t tropical coral reefs live in deep water
Because there’s not a light for photosynthesis
What must the turbidity be for coral survival
The seawater must have a very low turbidity
Why is low turbidity important
Turbid water reduces like penetration so photosynthesis would be reduced
What is the problem with having suspended solids in the water
It could settle on the reef blocking the coral stomach entrance
Why must the salinity be constant
Coral polyps do not have the ability to regulate water concentrations salinity is outside the narrow range of tolerance the corals will be killed by osmosis
Why are corals important fisheries
Call reef support many species that are exploited for food, including fish, crustaceans such as lobsters and molluscs
Why are corals important for medical discoveries
Many species that live in corals do not have spines, teeth or a hard shell to Protect themselves they may produce toxic chemicals which can be used as medicine
What drug is produced from chemicals in sponges from a coral reef in the Caribbean Sea?
The anti-viral drug AZT used to treat HIV/AIDS
How do corals control climate
Corals have a calcium carbonate shell each carbonate molecule Requires the absorption of a molecule of carbon dioxide so are growing coral reefs are an important carbon sink
How to Coral reefs act as erosion protection
Coral reefs absorb the energy of waves that would otherwise have eroded or washed away islands 
How do corals dissipate wave energy
To a regular and complex structure of corals dissipate the energy of waves efficiently
How do coral reefs allow for tourism
Ecotourism activities such as scuba diving and snorkelling
How does physical damage affect corals
Hard objects kill polyps as they are pushed against the hard limestone beneath the living cells
What sort of things can cause physical damage to Coral
Floating bottles, lost fishing gear, boat anchors and careless divers
Why is the collection of ornaments in souvenirs a threat to corals
Many species from coal reefs are collected to be sold as ornaments
How many coral species trade is restricted by CITES?
2000 species is restricted by CITES appendix 2
What is sedimentation
Turbid water carried by rivers or sediments disturbed by coastal development can cover and kill corals
What sort of pollution affects corals
Oil spills and sewage effluent
What is sewage effluent damaging to corals
Causes eutrophication
How is ocean acidification caused
An increase carbon dioxide concentration in the atmosphere means more carbon dioxide dissolves into the ocean producing carbonic acid
What is coral bleaching
Occurs when the symbiotic algae within the coral polyps are expelled
What can cause coral bleaching
Increased water temperatures caused by global climate change;
low oxygen levels due to high zooplankton activity caused by overfishing of the fish predators;
Pollution, including sewage, pesticides, cyanide and sunscreen products
What happens to bleached coral polyps overtime
As they are not dead they may regain algae in the future but Will grow slowly and can’t recover from damages easily
How can non-indigenous species be introduced? Tropical corals
From ballast water discharge from ships
Escaped fish and crustaceans from fish farms
Accidental or intentional releases from aquaria
What is an example of an nonindigenous species introduced to tropical coral reefs
The red lion fish was accidentally introduced to the Caribbean in the 1990s they are the now the general predator and have reduced the populations of many indigenous fish species
How can fishing be damaging to tropical Coral reefs
Overfishing produce fish populations and affect other interdependent species
nets dragging on sea bed destroy seagrass and coral
How can coastal developments damage corals (tropical)
Expansion of coastal towns, the construction tourist resort, Ports and Marinas can destroy coral reefs directly and increased ability causing damage to coral reefs near the development
How can a loss of associated habitats affect tropical coral reefs
Mangroves and seagrass beds help to trap spend sediments and reduce water turbidity if mangroves in seagrass beds are damaged then the coral reefs nearby become damaged to
Name two of the Management practices used in marine protected areas
Fixed mooring buoys instead of anchors
Divers can be taught not to touch coral
Fishing can be controlled or banned
Sustainable development of eco-tourism
Protecting associated habitats
How can fishing be controlled in tropical coral reefs
Length of fishing season restricted
Placing minimum catchable size
Imposing a maximum catchable size
Restrictions placed on damaging fishing methods
No take zones where fishing is banned
What may be done to protect tropical coral reefs from tourism?
Turtle nesting beaches may be protected to reduce disturbance
Spearfishing may be banned
Permanent mooring buoys may be installed
Collection of souvenirs may be banned
What is sustainable exploitation
Exploitation may be permitted but it may be restricted to ensure it is sustainable
What is reef creation
Artificial reefs have been created from concrete structures such as reef balls of a sinking structures that are made for other purposes such as old ships and oil rigs
